Prevalence of SARS-CoV-2 antibodies and associated factors in the adult population of Belgium: a general population cohort study between March 2021 and April 2022

BACKGROUND

This study assessed seroprevalence trends of SARS-CoV-2 antibodies in the Belgian adult population between March 2021 and April 2022, and explored factors associated with seropositivity and seroreversion among the vaccinated and unvaccinated population.

METHODS

A prospective longitudinal surveillance study was conducted within a random sample of the general population (18 + years) in Belgium, selected from the national register through a multistage sampling design. Participants provided a saliva sample and completed a survey questionnaire on three occasions: at baseline and in two follow-up waves. Outcome variables included (1) seropositivity, defined as the presence of SARS-CoV-2 antibodies, assessed with a semi-quantitative measure of anti-RBD (Receptor Binding Domain) IgG ELISA and (2) seroreversion, defined as passing from a positive to a negative antibody test between two measurements. Trends in SARS-CoV-2 antibody prevalence were assessed using binary logistic regression with contrasts applying post-stratification. Potential determinants of seropositivity were assessed through multilevel logistic regressions.

RESULTS

In total 6,178 valid observations were obtained from 2,768 individuals. SARS-CoV-2 antibody prevalence increased from 25.1% in the beginning of the study period to 92.3% at the end. Among the vaccinated population, factors significantly associated with higher seropositivity rates were being younger, having a bachelor diploma, living with others, having had a vaccine in the last 3 months and having received a nucleic-acid vaccine or a combination. Lower seropositivity rates were observed among vaccinated people with a neurological disease and transplant patients. Factors significantly associated with higher seropositivity rates among the unvaccinated population were having non-O blood type and being non-smoker. Among vaccinated people, the seroreversion rate was much lower (0.3%) in those who had received their latest vaccine in the last 3 months compared to those who had received their latest vaccine more than 3 months ago (2.7%) (OR 0.13; 95%CI 0.04-0.42).

CONCLUSIONS

The rapid increase in antibody seropositivity in the general adult population in Belgium during the study period was driven by the vaccination campaign which ran at full speed during this period. Among vaccinated people, seropositivity varied in function of the time since last vaccine, the type of vaccine, sociodemographic features and health status.

Yellow fever neutralizing antibody seroprevalence proportion and titers in previously vaccinated adults with chronic kidney disease

Studies on yellow fever vaccine (YF) in chronic kidney disease (CKD) patients are scarce. This cross-sectional study aimed to evaluate YF neutralizing antibody seroprevalence and titers in previously vaccinated adults with CKD, on dialysis (D-CKD) or not (ND-CKD), compared to healthy persons. The micro Plaque Reduction Neutralization-Horseradish Peroxidase (μPRN-HP) test was used. Antibody titers were expressed as the reciprocal of the highest dilution that neutralized the challenge virus by 50 % (μPRN50). Seropositivity cut-off was set at ≥ 1:100. We included 153 participants: 46 ND-CKD, 50 D-CKD and 57 healthy adults. Median ages were 58.3, 55 and 52.2 years, respectively. Median time since YF vaccination was 22.3, 18.5 and 48.3 months respectively. There were no statistically significant differences in YF seroprevalence and neutralizing antibodies titers among groups: 100 % of ND-CKD; 96 % of D-CKD and 100 % of healthy participants were seropositive. Geometric mean titers (GMT) were 818.5, 683.0 and 665.5, respectively (p = 0.289).

COVID-19 outbreak among employees of a German hospital: risk factor analysis based on a follow-up questionnaire and seroprevalence

BACKGROUND

The Co-FriSero study describes a COVID-19 outbreak at the Friedrichroda hospital in Thuringia, Germany, with 185 beds and 404 employees, at the onset of the pandemic between March 30th, 2020, and April 13th, 2020. This study aimed to analyze potential sources of SARS-CoV-2 transmission amongst hospital employees.

METHODS

After the outbreak, a comprehensive follow-up was conducted through a questionnaire and a seroprevalence study using two different immunoassays for IgG detection and a third for discordant results.

RESULTS

PCR screenings confirmed SARS-CoV-2 infection in 25 of 229 employees, with an additional 7 detected through serology. Statistical analysis indicated that direct patient contact, exposure to high flow ventilation in non-isolated rooms, direct contact with colleagues, shared use of recreational rooms, and carpooling were associated with an increased infection risk. Conversely, contact with family and friends, public transportation, public events, and use of locker rooms were not associated with infection. Male gender showed a lower infection likelihood, independent of age and other risk factors.

CONCLUSION

This study highlights the role of direct patient care and internal staff interactions in the spread of SARS-CoV-2 in the hospital setting. It suggests that non-traditional transmission routes like carpooling require consideration in pandemic preparedness.

Association of known SARS-CoV-2 serostatus and adherence to personal protection measures and the impact of personal protective measures on seropositivity in a population-based cross-sectional study (MuSPAD) in Germany

BACKGROUND

In 2020/2021 in Germany, several non-pharmacological interventions were introduced to lower the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated to what extent knowledge of prior infection with SARS-CoV-2 or vaccination status influenced the use of personal protection measures (PPM). Further, we were interested in the effect of compliance with PPM on SARS-CoV-2 serostatus.

METHODS

Data was based on a sequential, multilocal seroprevalence study (MuSPAD), carried out in eight locations from July 2020 to August 2021. We estimated the association between a known SARS-CoV-2 serostatus (reported positive PCR test or vaccination) and self-reported PPM behavior (hand hygiene, physical distancing, wearing face mask), just as the association of PPM compliance with seropositivity against nucleocapsid (NC), receptor-binding domain (RBD), and spike protein (S) antigens. We identified relevant variables and deduced adjustment sets with directed acyclic graphs (DAG), and applied mixed logistic regression.

RESULTS

Out of the 22,297 participants (median age: 54 years, 43% male), 781 were classified as SARS-CoV-2-infected and 3,877 had a vaccinated immune response. Vaccinated individuals were less likely to keep 1.5 m distance [OR = 0.74 (95% CI: 0.57-0.97)] and only partly physically distanced [OR = 0.71 (95% CI: 0.58-0.87)]. Participants with self-reported positive PCR test had a lower chance of adhering partly to physical distancing [OR = 0.70 (95% CI: 0.50-0.99)] in comparison to the reference group. Higher odds of additionally wearing a face mask was observed in vaccinated [OR = 1.28 (95% CI: 1.08-1.51)] even if it was not obligatory. Overall, among unvaccinated participants, we found little evidence of lower odds of seropositivity given mask wearing [OR: 0.91 (95% CI: 0.71-1.16)], physical distancing [OR: 0.84 (95% CI: 0.59-1.20)] and no evidence for completely adhering to hand cleaning [OR: 0.97 (95% CI: 0.29-3.22)].

CONCLUSIONS

A known confirmed prior infection and vaccination may have the potential to influence adherence to PPM.

Prevalence of SARS-CoV-2 infection among oral health care workers worldwide: A meta-analysis

OBJECTIVES

This systematic review aimed to answer the following question 'What are the worldwide prevalence of SARS-CoV-2 infection and associated factors among oral health-care workers (OHCWs) before vaccination?'

METHODS

Seven databases and registers as well as three grey databases were searched for observational studies in the field. Paired reviewers independently screened studies, extracted data and assessed the methodological quality. Overall seroprevalence for SARS-CoV-2 infection was analysed using a random-effect model subgrouped by professional category. Meta-regression was used to explore whether the Human Development Index (HDI) influenced the heterogeneity of results. The associated factors were narratively evaluated, and the certainty of the evidence was assessed using the GRADE approach.

RESULTS

Seventeen studies were included (five cohorts and twelve cross-sectional studies), summing 73 935 participants (54 585 dentists and 19 350 dental assistants/technicians) from 14 countries. The overall estimated pooled prevalence of SARS-CoV-2 infection among OHCWs was 9.3% (95% CI, 5.0%-14.7%; I2  = 100%, p < .01), being 9.5% for dentists (95% CI, 5.1%-15.0%; I2  = 100%, p < .01) and 11.6% for dental assistants/technicians (95% CI, 1.6%-27.4%; I2  = 99.0%, p < .01). In the meta-regression, countries with lower HDI showed higher prevalence of SARS-CoV-2 infection (p = .002). Age, comorbidities, gender, ethnicity, occupation, smoking, living in areas of greater deprivation, job role and location/municipalities, income and protective measures in dental settings were associated with positive serological SARS-CoV-2 test, with very low certainty of evidence.

CONCLUSIONS

The SARS-CoV-2 virus infected 9.3% of the OHCWs evaluated worldwide before vaccination. OHCWs should be included in policy considerations, continued research, monitoring and surveillance (PROSPERO CRD42021246520).

Korea Seroprevalence Study of Monitoring of SARS-COV-2 Antibody Retention and Transmission (K-SEROSMART): findings from national representative sample

OBJECTIVES

We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea.

METHODS

In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022.

RESULTS

In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%.

CONCLUSIONS

The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Dynamics of SARS-CoV-2 seroprevalence during the first year of the COVID-19 pandemic in the Northeast region of Brazil

In this household-based seroepidemiological survey, we analyzed the dynamics of SARS-CoV-2 seroprevalence during the first year of the COVID-19 pandemic in Sergipe State, Northeast Brazil, the poorest region of the country. A total of 16,547 individuals were tested using a rapid IgM-IgG antibody test and fluorescence immunoassay (FIA). Seroprevalence rates were presented according to age, sex, and geographic region. A comparative analysis was performed between the results obtained in July 2020 (peak of the first wave), August - November 2020 (end of the first wave), and February - March 2021 (beginning of the second wave). Seroprevalence rates in the three phases were estimated at 9.3% (95% CI 8.5-10.1), 12.0% (95% CI 11.2-12.9) and 15.4% (95% CI 14.5-16.4). At the end of the first wave, there was a rise in seroprevalence in the countryside (p < 0.001). At the beginning of the second wave, we found an increase in seroprevalence among women (p < 0.001), adults aged 20 to 59 years (p < 0.001), and the elderly (p < 0.001). In this phase, we found an increase in estimates both in metropolitan areas and in the countryside (p < 0.001). This study showed an increase in SARS-CoV-2 seroprevalence over the first year of the pandemic, with approximately one in six people having anti-SARS-CoV-2 antibodies at the beginning of the second wave of COVID-19. Furthermore, our results suggest a rapid spread of COVID-19 from metropolitan areas to the countryside during the first months of the pandemic.

Trend of immunity against measles and varicella zoster virus in healthcare workers in Korea

OBJECTIVE

To examine the seroprevalence of measles and varicella zoster virus (VZV) among healthcare workers (HCW) and evaluate the concordance between self-reported history of previous disease or vaccination and seropositivity.

DESIGN

A seroprevalence study and survey.

SETTING

A university-affiliated tertiary care hospital.

PARTICIPANTS

All HCWs working in high-risk services in 2017 underwent serologic tests and survey; all new HCWs employed in the subsequent years, serologic tests only.

METHODS

A serologic study was conducted using chemiluminescence immunoassay (2017) or enzyme immunoassays (2018 and later). HCWs who underwent serological testing in 2017 completed a self-administered questionnaire on their history of infection and vaccination.

RESULTS

A total of 10,278 and 9607 HCWs underwent serologic tests for measles and VZV IgG, respectively, from 2017 to 2022. The overall seropositivity rates for measles and VZV were 78.1 % and 92.8 %, respectively. Measles seropositivity declined gradually from >90 % in the HCWs born in the 1960s to <80 % in those born in the 1990s. There was a significant difference in measles seropositivity between the birth cohorts (BCs) 1967-1984 and 1985-1999 (P < 0.001; odds ratio, 1.16; 95 % confidence interval, 1.14-1.18). The seropositivity for VZV was stable, at >90 % in all BCs. The self-reported vaccination history was not independently associated with seropositivity, and the negative predictive value of the survey was very low (9.6 % and 13.1 %, respectively).

CONCLUSIONS

Measles seropositivity showed a substantial decline among HCWs born in 1985 or later, while varicella seropositivity remained high. The self-reported vaccination history was not sufficiently reliable for screening HCWs.

Seroprevalence of antibodies against SARS-CoV-2 in the Valencian Community (Spain) as of October 2022

OBJECTIVE

To estimate the seroprevalence of SARS-CoV-2 antibodies in the Valencian Community (Spain) in October 2022, when BA.5 was the predominant variant.

METHOD

Cross-sectional, region-wide, population-based serosurvey study in 88 randomly selected primary care centers of the Valencian Community.

RESULTS

Seroprevalence of anti-nucleocapsid (indicative of past infection) and total receptor binding domain (indicative of past infection or vaccination) antibodies was 71.0% (confidence interval [CI]: 67.8-74.2) and 98.4% (CI: 97.5-99.3), respectively. 66.7% (CI: 63.4-70.0) of the population shows hybrid immunity, but only 43.2% in those 80 and over.

CONCLUSIONS

The high proportion of hybrid immunity detected is relevant for public health strategies. A second vaccination booster was advisable in the elderly population.

SARS-CoV-2 seroepidemiology in Mongolia, 2020-2021: a longitudinal national study

Background

The COVID-19 pandemic has global impacts but is relatively understudied in developing countries. Mongolia, a lower-middle-income country, instituted strict control measures in early 2020 and avoided widespread transmission until vaccines became available in February, 2021. Mongolia achieved its 60% vaccination coverage goal by July 2021. We investigated the distribution and determinants of SARS-CoV-2 seroprevalence in Mongolia over 2020 and 2021.

Methods

We performed a longitudinal seroepidemiologic study aligned with WHO's Unity Studies protocols. We collected data from a panel of 5000 individuals in four rounds between October 2020 and December 2021. We selected participants through local health centres across Mongolia by age-stratified multi-stage cluster sampling. We tested serum for the presence of total antibodies against SARS-CoV-2 receptor-binding domain, and levels of anti-SARS-CoV-2 spike IgG and neutralising antibodies. We linked participant data with national mortality, COVID-19 case, and vaccination registries. We estimated population seroprevalence and vaccine uptake, as well as unvaccinated population prior-infection prevalence.

Findings

At the final round in late 2021, 82% (n = 4088) of participants completed follow-up. Estimated seroprevalence increased from 1.5% (95% CI: 1.2-2.0), to 82.3% (95% CI: 79.5-84.8) between late-2020 and late-2021. At the final round an estimated 62.4% (95% CI: 60.2-64.5) of the population were vaccinated, and of the unvaccinated population 64.5% (95% CI: 59.7-69.0) had been infected. Cumulative case ascertainment in the unvaccinated was 22.8% (95% CI: 19.1%-26.9%) and the overall infection-fatality ratio was 0.100% (95% CI: 0.088-0.124). Health workers had higher odds for being COVID-19 confirmed cases at all rounds. Males (1.72 (95% CI: 1.33-2.22)) and adults aged 20 and above (12.70 (95% CI: 8.14-20.26)) had higher odds for seroconverting by mid-2021. Among the seropositive, 87.1% (95% CI: 82.3%-90.8%) had SARS-CoV-2 neutralising antibodies by late 2021.

Interpretation

Our study enabled tracking of SARS-CoV-2 serological markers in the Mongolian population over one year. We found low SARS-CoV-2 seroprevalence in 2020 and early 2021, with seropositivity increasing over a 3-month interval in 2021 due to vaccine roll out and rapid infection of most of the unvaccinated population. Despite high seroprevalence in Mongolia amongst both vaccinated and unvaccinated individuals by end-2021, the SARS-CoV-2 Omicron immune escape variant caused a substantial epidemic.

Funding

World Health Organization, WHO UNITY Studies initiative, with funding by the COVID-19 Solidarity Response Fund and the German Federal Ministry of Health (BMG) COVID-19 Research and development. The Ministry of Health, Mongolia partially funded this study.

Risk factors associated with Hepatitis E virus infection in kidney transplant recipients in a single tertiary Center in the United States

BACKGROUND

Hepatitis E virus (HEV), the causative agent of hepatitis E, is a common but self-limiting disease. However, in immunosuppressed kidney transplant 47 recipients (KTRs), HEV infection can become chronic. We investigated risk factors associated with HEV infection among 271 KTRs at the Johns Hopkins Hospital transplanted between 1988 and 2012.

METHODS

HEV infection was defined as having positive anti-HEV IgM, anti-HEV IgG, or HEV RNA. The risk factors included: age at transplant, sex, hemodialysis/peritoneal dialysis, plasmapheresis, transfusions, community urbanization, and other socioeconomic factors. Logistic regression was used to determine independent risk factors associated with HEV infection.

RESULTS

Out of 271 KTRs, 43 (16%) had HEV infection though not active disease. HEV infection in KTRs was associated with older age (≥45 years; OR = 4.04; 95% CI = 1.81-57 10.03; p = 0.001) and living in communities with low proportions of minorities (OR = 0.22; 95% 58 CI = 0.04-0.90; p = 0.046).

CONCLUSION

KTRs who had HEV infection may be at an increased risk of developing chronic HEV.

Is there a higher risk of exposure to Coxiella burnetii for pre-clinical veterinary students?

Coxiella burnetii is globally distributed but evidence of zoonotic transmission in the Caribbean region is scarce. The bacterium presence is suspected on the Caribbean island of St. Kitts. The risk of exposure of veterinary students was reported in other regions of the world but is not documented in the Caribbean region. The present study aimed to evaluate the risk of exposure to C. burnetii for pre-clinical veterinary students (mostly coming from the U.S.) attending an island-based veterinary school. A cross-sectional study was conducted to compare incoming and outgoing veterinary students' seroprevalence. Serology was performed using indirect immunofluorescence assay to test Coxiella burnetii Phase I and Phase II immunoglobulins M and G. Background data were gathered using a standardized questionnaire. A parallel study enrolled veterinary school employees in the same university. Of the 98 participants (48 incoming and 50 outgoing students), 41 (41.8%, 95 %CI: 31.9-52.2) were seropositive to C. burnetii. There was no significant difference between the two groups (45.8% for incoming vs. 38.0% for outgoing students) (p = 0.4). No risk factors (demographic, animal handling practices or background) were significantly more reported in the seropositive group. In the employee study, the seroprevalence was high with 8/15 seropositives (53.3%, 95 %CI: 26.6-78.7). Pre-clinical veterinary students do not have a higher risk of exposure to C. burnetii by attending the veterinary school in St. Kitts, but they are highly exposed before arrival on the island (seroprevalence of 45.8%). Most of these participants had experience with animals either through farming or previous veterinary technician employment. This indicates a high exposure in the U.S. young population aiming to become veterinarians. There is an urgent need to increase C. burnetii surveillance in animals and humans to apply relevant prevention and control measures, including recommendations for vaccination of students and professionals at risk.

Seroprevalence of Helicobacter pylori in human immunodeficiency virus-infected patients in a tertiary care hospital in Busan, South Korea

INTRODUCTION

Human immunodeficiency virus (HIV) infection management has recently become more successful. While the life expectancy of HIV-infected patients increased, the prevalence of non-acquired immunodeficiency syndrome-defining cancers, such as gastric cancer, also increased. Helicobacter pylori is associated with gastric cancer, the most common cancer and the fourth leading cause of cancer-related deaths in South Korea, which has the highest incidence of chronic gastric mucosa inflammation. Here, the seroprevalence and risk factors of H. pylori infection in Korean HIV-infected patients were evaluated.

METHODS

Three hundred HIV-infected patients attending the Outpatient Department of Pusan National University Hospital were prospectively enrolled from October 2018 to February 2019. Socio-demographic information was evaluated using questionnaires, and the serological status of H. pylori infection was analyzed for anti-H. pylori IgG antibodies.

RESULTS

The overall seropositivity of H. pylori was 32.7%, and 254 patients (84.7%) were male. The risk factors significantly associated with H. pylori seropositivity were: age of 40-49 years (odds ratio [OR] = 5.00; 95% confidence interval [CI] 1.30-19.17), age of 50-59 years (OR = 3.93; 95% CI 1.05-14.73), CD4 cell counts of 350-500/μL (OR = 4.23; 95% CI 1.53-11.65), CD4 cell counts ≥500/μL (OR = 2.78; 95% CI 1.15-6.72), and a weekly average alcohol consumption of at least one alcoholic beverage (OR = 1.78; 95% CI 1.05-2.99).

CONCLUSIONS

The seroprevalence of H. pylori is significantly associated with alcohol consumption, high CD4 cell count, and the age group of 40-59 years.

Seroprevalence of viral infectious diseases and associated factors in Korean patients with inflammatory bowel diseases

BACKGROUND/AIMS

Data on the immunoprotective status against measles, mumps, rubella, varicella zoster virus (VZV), hepatitis A virus (HAV), and Epstein-Barr virus (EBV) infection in patients with inflammatory bowel disease (IBD) are still lacking. Therefore, we investigated the seropositivity rates for viral infectious diseases and the associated factors in Korean patients with IBD.

METHODS

In this retrospective cohort study, serum immunoglobulin G antibody positivity rates against measles virus, mumps virus, rubella virus, VZV, HAV, and EBV viral capsid antigen (VCA) were measured in patients with Crohn's disease or ulcerative colitis (UC) who first visited the IBD clinic. Seropositivity rates and their associated factors were analyzed.

RESULTS

Between January 2016 and December 2018, 263 patients were enrolled (male, 167 [67.3%]; UC, 134 [50.9%]). The median age at serological test was 30 years (interquartile range, 22 to 46). The seropositivity rates were 84.0%, 85.2%, 66.5%, 87.4%, 50.0%, and 93.7% for measles, mumps, rubella, VZV, HAV, and EBV, respectively. Younger age at serological test was associated with seronegative status for measles (adjusted odds ratio [aOR], 0.92; 95% confidence interval [CI], 0.88 to 0.96), VZV (aOR, 0.83; 95% CI, 0.74 to 0.93), and HAV (aOR, 0.93; 95% CI, 0.91 to 0.95). Furthermore, IBD type-UC was associated with seronegative status against VZV (aOR, 0.33; 95% CI, 0.11 to 0.99).

CONCLUSION

Seropositivity rates for common viral infectious diseases in Korean patients with IBD were similar to those of the general population. In the younger age group, protective immunity against measles, VZV, and HAV is required, with proper vaccination, as necessary.

Variation in SARS-CoV-2 seroprevalence in children in the region of Asturias, Northern Spain

BACKGROUND

Updated seroprevalence estimates are important to describe the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) landscape and to guide public health decisions. The aims are to describe longitudinal changes in seroprevalence in children in a region in Northern Spain and to analyze factors associated with SARS-CoV-2 seropositivity.

METHODS

Prospective multicenter longitudinal study with subjects recruited from July to September 2020. Children (up to 14 years old) were included and followed up until September 2021. Venous blood samples were collected every six months during three testing rounds and were analyzed for SARS-CoV-2 antibodies. The data regarding epidemiological features, contact tracing, symptoms, and virological tests were collected. The evolution of SARS-CoV-2 seroprevalence during the study and the differences between children with positive and negative SARS-CoV-2 antibody tests were analyzed.

RESULTS

Two hundred children were recruited (50.5% girls, median age 9.7 years). The overall seroprevalence increased from round 1 [1.5%, 95% confidence interval (CI) 0.3%-4.3%] to round 2 (9.1%, 95% CI 4.6%-12.7%) and round 3 (16.6%, 95% CI 9.5%-19.6%) (P < 0.001). Main changes occurred in children aged zero to four years (P = 0.001) who lived in urban areas (P < 0.001). None of the children who were previously positive became seronegative. Following multivariable analysis, three variables independently associated with SARS-CoV-2 seropositivity were identified: close contact with coronavirus disease 2019 (COVID-19) confirmed or suspected cases [odds ratio (OR) = 3.9, 95% CI 1.2-12.5], previous positive virological test (OR = 17.1, 95% CI 3.7-78.3) and fatigue (OR = 18.1, 95% CI 1.7-193.4).

CONCLUSIONS

SARS-CoV-2 seroprevalence in children has remarkably increased during the time of our study. Fatigue was the only COVID-19-compatible symptom that was more frequent in seropositive than in seronegative children.

The Study to Investigate COVID-19 Infection in People Living in Ireland (SCOPI): A seroprevalence study, June to July 2020

BackgroundRobust data on SARS-CoV-2 population seroprevalence supplement surveillance data in providing evidence for public health action.AimTo conduct a SARS-CoV-2 population-based seroprevalence survey in Ireland.MethodsUsing a cross-sectional study design, we selected population samples from individuals aged 12-69 years in counties Dublin and Sligo using the Health Service Executive Primary Care Reimbursement Service database as a sampling frame. Samples were selected with probability proportional to the general population age-sex distribution, and by simple random sampling within age-sex strata. Antibodies to SARS-CoV-2 were detected using the Abbott Architect SARS-CoV-2 IgG Assay and confirmed using the Wantai Assay. We estimated the population SARS-CoV-2 seroprevalence weighted for age, sex and geographic area.ResultsParticipation rates were 30% (913/3,043) and 44% (820/1,863) in Dublin and Sligo. Thirty-three specimens had detectable SARS-CoV-2 antibodies (1.9%). We estimated weighted seroprevalences of 3.12% (95% confidence interval (CI): 2.05-4.53) and 0.58% (95% CI: 0.18-1.38) for Dublin and Sligo, and 1.69% (95% CI: 1.13-2.41) nationally. This equates to an estimated 59,482 (95% CI: 39,772-85,176) people aged 12-69 years nationally having had infection with SARS-CoV-2, 3.0 (95% CI: 2.0-4.3) times higher than confirmed notifications. Ten participants reported a previous laboratory-confirmed SARS-CoV-2 -infection; eight of these were antibody-positive. Twenty-five antibody-positive participants had not reported previous laboratory-confirmed infection.ConclusionThe majority of people in Ireland are unlikely to have been infected with SARS-CoV-2 by June-July 2020. Non-pharmaceutical public health measures remained key pending widespread availability of vaccination, and effective treatments.

Hepatitis A Outbreak in a Facility for the Disabled, Gyeonggi Province, Korea: An Epidemiological Investigation

Objectives:

The number of cases of hepatitis A virus (HAV) infections has sharply increased in Korea, especially among young adults. In this study, an HAV outbreak in a facility for disabled people was investigated, and we found epidemiological differences both between 2 different generations and between generally abled and disabled groups.

Methods:

We analyzed the incubation period and attack rate of an HAV outbreak and investigated the prevalence of HAV antibodies among the staff and residents of a facility for the disabled. We performed a retrospective cohort study during the HAV outbreak, which lasted from February 8 to 25, 2019, including examinations of HAV antibody tests and post-exposure HAV vaccination for the staff or residents of the facility.

Results:

There were 9 confirmed cases in 2 staff members and 7 residents. Among 53 people (30 staff and 23 residents), except for the 9 confirmed cases and 1 staff member with a known history of HAV infection, HAV seroprevalence was seen in 16.7% of the staff under 40 years of age and 95.2% of those over 40 years of age, while the corresponding rates in the residents were 0.0% and 58.8%, respectively.

Conclusions:

This result implies that it is necessary to prioritize HAV vaccination for vulnerable groups and workers of residential care facilities.

SARS-CoV-2 antibodies in employees working in non-medical contact-intensive professions in the Netherlands: Baseline data from the prospective COco-study

COVID-19 has made a global impact since early 2020, requiring characterization of the SARS-CoV-2 virus, including transmission risk. The COco-study aims to evaluate the risk for COVID-19 infections in two non-medical contact-intensive professions. COco is a prospective cohort study evaluating SARS-CoV-2 antibodies in hairdressers and hospitality personnel in the province of North-Brabant in the Netherlands, using a total antibody enzyme-linked immunosorbent assay. Baseline data from June/July 2020 were analyzed. Participants filled out a questionnaire, providing information on demographics, health, work situation, and risk factors for COVID-19. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using logistic regression. In June/July 2020, 497 participants were enrolled: 236 hairdressers, 259 hospitality employees, and two participants worked in both industries. Hospitality staff was more frequently seropositive than hairdressers (14.2% versus 8.0%, respectively; OR 1.9, 95% CI 1.1-3.4). Furthermore, a high education level (OR 3.0, 95% CI: 1.7-5.6) and increased alcohol use (OR, 7 glasses per week increment: 1.3, 95% CI: 1.1-1.5) were associated with seropositivity. Of the 56 seropositive participants, 18 (32%) had not experienced any COVID-19 symptoms. The symptoms anosmia/ageusia differed most evidently between seropositive and seronegative participants (53.6% versus 5.7%, respectively; P < 0.001 (chi-squared test)). In conclusion, four months after the first identified COVID-19 patient in the Netherlands, employees in the hospitality industry had significantly more frequently detectable SARS-CoV-2 antibodies than hairdressers.

Low SARS-CoV-2 seroprevalence but high perception of risk among healthcare workers at children's hospital before second pandemic wave in Germany

BACKGROUND

Healthcare workers are considered a particularly high-risk group during the coronavirus disease 2019 (COVID-19) pandemic. Healthcare workers in paediatrics are a unique subgroup: they come into frequent contact with children, who often experience few or no symptoms when infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and, therefore, may transmit the disease to unprotected staff. In Germany, no studies exist evaluating the risk of COVID-19 to healthcare workers in paediatric institutions.

METHODS

We tested the staff at a large children's hospital in Germany for immunoglobulin (Ig) G antibodies against the nucleocapsid protein of SARS-CoV-2 in a period between the first and second epidemic wave in Germany. We used a questionnaire to assess each individual's exposure risk and his/her own perception of having already been infected with SARS-CoV-2.

RESULTS

We recruited 619 participants from all sectors, clinical and non-clinical, constituting 70% of the entire staff. The seroprevalence of SARS-CoV-2 antibodies was 0.325% (95% confidence interval 0.039-1.168). Self-perceived risk of a previous SARS-CoV-2 infection decreased with age (odds ratio, 0.81; 95% confidence interval, 0.70-0.93). Having experienced symptoms more than doubled the odds of a high self-perceived risk (odds ratio, 2.18; 95% confidence interval, 1.59-3.00). There was no significant difference in self-perceived risk between men and women.

CONCLUSIONS

Seroprevalence was low among healthcare workers at a large children's hospital in Germany before the second epidemic wave, and it was far from a level that confers herd immunity. Self-perceived risk of infection is often overestimated.

Severe chickenpox disease and seroprevalence in Sweden - implications for general vaccination

OBJECTIVES

To describe the current panorama of severe chickenpox disease and seroprevalence in Sweden, as a basis for the approaching decision on universal vaccination.

METHODS

We included patients discharged with an International Classification of Diseases, 10th revision-code for chickenpox (B01.1-9) in eight pediatric and infectious diseases departments in Stockholm and Gothenburg in 2012-2014 and reviewed their medical charts. Further, residual serum samples collected from 16 laboratories across Sweden were analyzed for varicella zoster IgG-antibodies to investigate the age-specific seroprevalences.

RESULTS

In all, 218 children and 46 adults were included in the hospital-based study, 87.2% of children and 63.0% of adults had complications. An underlying condition was not associated with an increased risk for complication. In children dehydration (31.7%), bacterial skin infections (29.8%) and neurological involvement (20.6%) were most frequent complications. Among adult cases, 63 % were born abroad. The seroepidemiological analysis included 957 patient samples. Seroprevalence was 66.7% at 5 years and 91.5% at 12 years. Infants and adolescents/adults were overrepresented among admitted patients compared to seroprevalence data.

CONCLUSIONS

Half of all complications in hospitalized chickenpox cases was seen in previously healthy children, which supports universal childhood vaccination. Adult migrants was a risk group for chickenpox hospitalization. Age-specific seroprevalence was similar to neighboring countries.

Population-Based Estimates of SARS-CoV-2 Seroprevalence in Houston, TX as of September 2020

BACKGROUND

In contrast to studies that relied on volunteers or convenience sampling, there are few population-based SARS-CoV-2 seroprevalence investigations and most were conducted early in the pandemic. The health department of the fourth largest city in the U.S. recognized that sound estimates of viral impact were needed to inform decision-making.

METHODS

Adapting standardized disaster research methodology in September 2020, the city was divided into high and low strata based on RT-PCR positivity rates, and census block groups within each stratum were randomly selected with probability proportional to size, followed by random selection of households within each group. Using two immunoassays, the proportion of infected individuals was estimated for the city, as well as by positivity rate and by sociodemographic and other characteristics. The degree of under ascertainment of seroprevalence was estimated based on RT-PCR positive cases.

RESULTS

Seroprevalence was estimated to be 14% with a near two-fold difference in areas with high (18%) versus low (10%) RT-PCR positivity rates and was four times higher compared to case-based surveillance data.

CONCLUSIONS

Seroprevalence was higher than previously reported and is greater than that estimated from RT-PCR data. Results will be used to inform public health decisions about testing, outreach, and vaccine rollout.

SARS-CoV-2 Seroprevalence in Lithuania: Results of National Population Survey

SUMMARY BACKGROUND

Betacoronavirus SARS-CoV-2 has spread in early 2020 worldwide just in several months. The official statistics are consistently collected, but this is mainly based on symptomatic reports. This study was aimed to estimate the seroprevalence of SARS-CoV-2 infection in Lithuanian population.

MATERIALS AND METHODS

Study was conducted during August-September 2020 in 6 municipalities of Lithuania. The sample comprised 3087 adult participants from the general population (mean age 53.7 years, 64% female). SARS-CoV-2 antibodies were assessed using AMP IgM/IgG Rapid Test, other data were based on self-report. Seroprevalence was assessed as a crude estimate and as adjusted by sensitivity-specificity of the test.

RESULTS

The crude seroprevalence in the total sample was 1.9%, the adjusted - 1.4%, ranging from 0.8% to 2.4% across municipalities. Among seroprevalent cases, 67.2% had IgG, 29.3% had IgM, and 3.5% had both IgG and IgM. An increased risk for seropositive test was observed among people who reported having had close contacts with SARS-CoV-2 positives (OR=5.49, p<0.001). At the borderline significance were female gender (OR=1.75, p=0.082) and non-smoking status (OR=2.95, p=0.072). Among the seropositive participants, 69.0% reported having had no COVID-19 symptoms since 1 March 2020, while 31.0% reported having had at least one of the symptoms.

CONCLUSIONS

The SARS-CoV-2 seroprevalence in Lithuanian sample in August-September 2020 was 1.4%, ranging from 0.8% to 2.4% across municipalities. Given the overall official data, by the end of study (11 September 2020) the total COVID-19 rate in Lithuania was 117.5 per 100,000 population or 0.12%. This suggests more than 10 times higher prevalence of virus across the population than the official estimates.

Hospital-Wide SARS-CoV-2 seroprevalence in health care workers in a Spanish teaching hospital

INTRODUCTION

Hospital-wide SARS-CoV-2 seroprevalence is rarely explored and can identify areas of unexpected risk. We determined the seroprevalence against SARS-CoV-2 in all health care workers (HCW) at a hospital.

METHODS

Cross-sectional study (14-27/04/2020). We determined SARS-CoV-2 IgG by ELISA in all HCW including external workers of a teaching hospital in Madrid. They were classified by professional category, working area, and risk for SARS-CoV-2 exposure.

RESULTS

Among 2919 HCW, 2590 (88,7%) were evaluated. The mean age was 43.8 years (SD 11.1), and 73.9% were females. Globally, 818 (31.6%) workers were IgG positive with no differences for age, sex or previous diseases. Of these, 48.5% did not report previous symptoms. Seropositivity was more frequent in high- (33.1%) and medium- (33.8%) than in low-risk areas (25.8%, p=0.007), but not for hospitalization areas attending COVID-19 and non-COVID-19 patients (35.5 vs 38.3% p>0.05). HWC with a previous SARS-CoV2 PCR-positive test were IgG seropositive in 90.8%. By multivariate logistic regression analysis seropositivity was significantly associated with being physicians (OR 2.37, CI95% 1.61-3.49), nurses (OR 1.67, CI95% 1.14-2.46), nurse assistants (OR 1.84, CI95% 1.24-2.73), HCW working at COVID-19 hospitalization areas (OR 1.71, CI95% 1.22-2.40), non-COVID-19 hospitalization areas (OR 1.88, CI95% 1.30-2.73), and at the Emergency Room (OR 1.51, CI95% 1.01-2.27).

CONCLUSIONS

Seroprevalence uncovered a high rate of infection previously unnoticed among HCW. Patients not suspected of having COVID-19 as well as asymptomatic HCW may be a relevant source for nosocomial SARS-CoV-2 transmission.

Detection of Coxiella burnetii antibodies in sheep and cattle on a veterinary campus in St. Kitts: Implications for one health in the Caribbean region

Coxiella burnetii is a ubiquitous zoonotic bacterium reported worldwide that causes Q-fever. Infections result in profound economic losses to livestock producers by causing abortions and low birth weights. Current information about the disease in the Caribbean region is scarce. With multiple small islands and territories, it is often considered that the bacterium is absent or circulates at a low prevalence. Our study aimed to determine whether sheep and cattle housed at a veterinary campus in St Kitts had previous exposure to C. burnetii. Blood samples were taken from cattle (n = 63; 72% of the herd) and sheep (n = 133; 71% of the flock). Antibodies to C. burnetii were detected by a commercial indirect enzyme-linked immunosorbent assay (IDvet® ELISA) test. The seroprevalence was estimated at 26.3% (95% CI: 19.1–34.7%) in sheep and 0% (95% CI: 0–5.7%) in cattle. Sheep importation to St. Kitts is very rare, thus, these results suggest that C. burnetii is present on the island. The seronegativity of all the cattle highlights the absence of the bacterium on the veterinary campus. The high seroprevalence in sheep, however, has potentially important implications for animal health and public health as well as for wildlife conservation. Further investigation about animal seroprevalence and human exposure are warranted in St. Kitts and in the Caribbean region.

•

Seroprevalence in sheep from a veterinary university was 26.3%

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No cattle from the university were seropositive

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Risk for human and animal health is likely to be important in St. Kitts

•

There is a need to investigate the prevalence of Coxiella burnetii in Caribbean region

Cumulative incidence and diagnosis of SARS-CoV-2 infection in New York

PURPOSE

New York State (NYS) is an epicenter of the SARS-CoV-2 pandemic in the United States. Reliable estimates of cumulative incidence in the population are critical to tracking the extent of transmission and informing policies.

METHODS

We conducted a statewide seroprevalence study in a 15,101 patron convenience sample at 99 grocery stores in 26 counties throughout NYS. SARS-CoV-2 cumulative incidence was estimated from antibody reactivity by first poststratification weighting and then adjusting by antibody test characteristics. The percent diagnosed was estimated by dividing the number of diagnoses by the number of estimated infection-experienced adults.

RESULTS

Based on 1887 of 15,101 (12.5%) reactive results, estimated cumulative incidence through March 29 was 14.0% (95% confidence interval [CI]: 13.3%-14.7%), corresponding to 2,139,300 (95% CI: 2,035,800-2,242,800) infection-experienced adults. Cumulative incidence was highest in New York City 22.7% (95% CI: 21.5%-24.0%) and higher among Hispanic/Latino (29.2%), non-Hispanic black/African American (20.2%), and non-Hispanic Asian (12.4%) than non-Hispanic white adults (8.1%, P < .0001). An estimated 8.9% (95% CI: 8.4%-9.3%) of infections in NYS were diagnosed, with diagnosis highest among adults aged 55 years or older (11.3%, 95% CI: 10.4%-12.2%).

CONCLUSIONS

From the largest U.S. serosurvey to date, we estimated >2 million adult New York residents were infected through late March, with substantial disparities, although cumulative incidence remained less than herd immunity thresholds. Monitoring, testing, and contact tracing remain essential public health strategies.

Cumulative incidence and diagnosis of SARS-CoV-2 infection in New York

PURPOSE

New York State (NYS) is an epicenter of the SARS-CoV-2 pandemic in the United States. Reliable estimates of cumulative incidence in the population are critical to tracking the extent of transmission and informing policies.

METHODS

We conducted a statewide seroprevalence study in a 15,101 patron convenience sample at 99 grocery stores in 26 counties throughout NYS. SARS-CoV-2 cumulative incidence was estimated from antibody reactivity by first poststratification weighting and then adjusting by antibody test characteristics. The percent diagnosed was estimated by dividing the number of diagnoses by the number of estimated infection-experienced adults.

RESULTS

Based on 1887 of 15,101 (12.5%) reactive results, estimated cumulative incidence through March 29 was 14.0% (95% confidence interval [CI]: 13.3%-14.7%), corresponding to 2,139,300 (95% CI: 2,035,800-2,242,800) infection-experienced adults. Cumulative incidence was highest in New York City 22.7% (95% CI: 21.5%-24.0%) and higher among Hispanic/Latino (29.2%), non-Hispanic black/African American (20.2%), and non-Hispanic Asian (12.4%) than non-Hispanic white adults (8.1%, P < .0001). An estimated 8.9% (95% CI: 8.4%-9.3%) of infections in NYS were diagnosed, with diagnosis highest among adults aged 55 years or older (11.3%, 95% CI: 10.4%-12.2%).

CONCLUSIONS

From the largest U.S. serosurvey to date, we estimated >2 million adult New York residents were infected through late March, with substantial disparities, although cumulative incidence remained less than herd immunity thresholds. Monitoring, testing, and contact tracing remain essential public health strategies.

Prevalence of Zika virus neutralizing antibodies in healthy adults in Vietnam during and after the Zika virus epidemic season: a longitudinal population-based survey

Background

Between 2016 and 2019, 265 cases of Zika virus (ZIKV) infection were reported in Vietnam, predominantly in southern Vietnam. In 2016, a case of ZIKV-associated microcephaly was confirmed in the Central Highlands, and several members of the infant’s family were confirmed to be infected with ZIKV. The study aims to determine the level of immunity to ZIKV in the general population of the ZIKV epidemic region.

Methods

A total of 879 serum samples were collected from 801 participants between January 2017 and July 2018, during and after the ZIKV epidemic in Vietnam. The samples were tested for anti-ZIKV immunoglobulin M (IgM) and immunoglobulin G (IgG), and anti-dengue virus (DENV) IgG antibodies using enzyme-linked immunosorbent assays (ELISA). Plaque-reduction neutralization test (PRNT) for ZIKV was performed on all samples, and for DENV on the samples that ZIKV neutralizing antibody positive.

Results

A total of 83 (10.3%) participants had anti-ZIKV IgM. Of the 83, 6 were confirmed to be ZIKV antibodies positive using PRNT and anti-ZIKV IgG ELISA. Of the 718 participants who were anti-ZIKV IgM negative, a further 3 cases were confirmed as positive for antibodies against ZIKV. Of the 9 participants with ZIKV infection, 5 lived in the same village as the infant with ZIKV-associated microcephaly and the other 4 lived in 2 neighboring communes. Repeat samples were collected from the 83 ZIKV IgM positive participants 1.5 years after the first collection. No new cases of ZIKV infection were detected. In addition, 2 of 3 participants with anti-ZIKV NS1 IgG demonstrated a 4- to 8-fold increase in ZIKV neutralizing antibody titer.

Conclusions

ZIKV was present in the area around Krong Buk, with the rate of ZIKV-specific antibodies was 1.1% in the community since at least 2016. While the low levels of circulation together with low seroprevalence suggests a limited outbreak in the region, the results also reflect on low levels of protective immunity to Zika within the population. These results provide a better understanding of the current ZIKV epidemic status in the region and demonstrate a need for implementation of more effective ZIKV infection control measures.

Hepatitis E Virus Infection in an Italian Cohort of Hematopoietic Stem Cell Transplantation Recipients: Seroprevalence and Infection

Chronic hepatitis E virus (HEV) infection in hematopoietic stem cell transplantation (HSCT) recipients is an emerging threat. The aim of this study was to provide data on the HEV burden in an Italian cohort of HSCT recipients and analyze risk factors for HEV seropositivity. This retrospective study reports data from 596 HSCT recipients compiled between 2010 and 2019. It included patients who underwent transplantation between 2010 and 2015 for whom pretransplantation (n = 419) and post-transplantation (n = 161) serum samples were available and tested retrospectively, as well as patients in whom prospective HEV testing was performed during the standard care: pre-HSCT IgG screening in 144, pre-HSCT HEV-RNA screening in addition to IgG screening in 60, and HEV-RNA testing in case of clinical suspicion of HEV infection in 59 (26 of whom were also included in the IgG screening cohorts). The rate of pre-HSCT HEV-IgG positivity was 6.0% (34 of 563). Older age was an independent risk factor for seropositivity (P = .039). None of the 34 HEV-IgG-positive patients had detectable HEV-RNA. One case of transient HEV-RNA positivity pre-HSCT was identified through screening. Two patients were diagnosed with chronic HEV hepatitis, and 1 patient was successfully treated with ribavirin. The burden of HEV infection in HSCT recipients in Italy is limited, and pre-HSCT screening appears to be of no benefit. Timely diagnosis of HEV infection with HEV-RNA is mandatory in cases of clinical suspicion.

Measles Outbreak in a Rural Population in Bahar District, Hamadan Province, West of Iran in 2018

Background: Measles is in elimination phase in Iran. Following occurrence of two cases of measles in two children under six years old with the history of measles immunization in one of the villages affiliated to Bahar District, west of Hamadan Province, northwest of Iran, this study was conducted to determine the immunity status of people living in the village affected by the measles outbreak in spring of 2018.

Study design: A cross-sectional (descriptive-analytical) study.

Methods: Overall, 272 populations of 0-40 yr old in the village affected by outbreak were enrolled. Multistage sampling was used for choosing participants. The data collection tool was a researcher-made checklist used to collect epidemiological data including demographic characteristics and vaccination status. Blood samples were taken from them and sent to the measles reference laboratory for IgG testing. The amount of optical density (OD) greater than 0.2 was considered as positive and less than 0.1 negative, respectively.

Results: The mean age of the study population was 17.4 ±11.8 yr and the sex ratio was almost the same. Levels of antibodies against measles were positive in 63.24%, intermediate in 12.5% and negative in 24.26%. There was no significant difference between the immunity status of the subjects with gender (P=0.236) and age group (P=0.113). Pearson correlation results showed that in males there was a significant positive correlation between the age of the participants and the serum IgG level (r = 0.26, P=0.003).

Conclusion: Measles immunity in communities is not sufficient to prevent outbreaks and small epidemics, and it is recommended that periodically, serological assessments carried out at community level and especially at high-risk groups.

Seroprevalence of mumps in healthcare workers in South Korea

Mumps is contagious disease and maintaining immunity to mumps in healthcare worker (HCW) is important for preventing transmission in the hospital. We evaluated the seroprevalence of mumps in HCWs in a tertiary care hospital in Republic of Korea. A total of 6,055 HCWs born between 1950 and 1995 underwent antibody testing. The overall seropositivity rate of mumps was 87% (95% confidence interval, 86%-87%). Our data indicates that, in Korean HCWs, testing for mumps antibody followed by mumps vaccination is more appropriate than routine mumps vaccination without testing for mumps antibody.

Seropositive rate of the anti-hepatitis A immunoglobulin G antibody in maintenance hemodialysis subjects from two hospitals in Korea

BACKGROUND/AIMS

Hepatitis A virus (HAV) is a self-limiting infectious disease, but 1% of subjects develop fulminant hepatitis. The prevalence of the anti-HAV immunoglobulin G (IgG) antibody in hemodialysis subjects in Korea remains unknown. The purpose of this study was to describe and compare the seropositive rate of anti-HAV antibody among hemodialysis subjects in two hospitals according to age group.

METHODS

A total of 170 hemodialysis subjects were evaluated for the seropositive rate of the anti-HAV IgG antibody and its titer.

RESULTS

Of the 170 maintenance hemodialysis subjects in two hospitals (Kangnam 92 vs. Chuncheon 78), 79 (46.5%) were male. The mean age was 53.2 years old, and 94.1% of the subjects were over 40 years old. The median vintage of hemodialysis was 29.0 months. Anti-HAV antibody was found in 163 subjects (95.9%), with no significant difference between the two areas (Kangnam 97.8% [n = 90] vs. Chuncheon 93.6% [n = 73]). Subjects younger than 40 years old showed a seropositive rate of 50%, while the seropositive rate increased with age for subjects aged 40 or older (p for trend < 0.001). Seropositive subjects from Kangnam showed a higher anti-HAV antibody titer than those from Chuncheon (median: Kangnam 14.2 vs. Chuncheon 11.7). Only age influenced seropositivity. The only factor that influenced the antibody level was the location of hospital (p < 0.001).

CONCLUSION

The seropositive rate of the anti-HAV antibody in hemodialysis subjects was 95%, which is similar to findings in the general population. Active immunization against hepatitis A is strongly recommended for hemodialysis subjects under 40 years of age after anti-HAV testing.

Estimated dengue force of infection and burden of primary infections among Indian children

Background

Comprehensive, age-stratified dengue surveillance data are unavailable from India and many more dengue cases occur than are reported. Additional information on dengue transmission dynamics can inform understanding of disease endemicity and infection risk.

Methods

Using age-stratified dengue IgG seroprevalence data from 2556 Indian children aged 5–10 years, we estimated annual force of infection (FOI) at each of 6 sites using a binomial regression model. We estimated the ages by which 50 and 70% of children were first infected; and predicted seroprevalence in children aged 1–10 years assuming constant force-of-infection. Applying these infection rates to national census data, we then calculated the number of primary dengue infections occurring, annually, in Indian children.

Results

Annual force-of-infection at all sites combined was 11.9% (95% CI 8.8–16.2), varying across sites from 3.5% (95% CI 2.8–4.4) to 21.2% (95% CI 18.4–24.5). Overall, 50 and 70% of children were infected by 5.8 (95% CI 4.3–7.9) and 10.1 (95% CI 7.4–13.7) years respectively. In all sites except Kalyani, > 70% of children had been infected before their 11th birthday, and goodness-of-fit statistics indicated a relatively constant force-of-infection over time except at two sites (Wardha and Hyderabad). Nationwide, we estimated 17,013,527 children (95% CI: 14,518,438- 19,218,733), equivalent to 6.5% of children aged < 11 years, experience their first infection annually.

Conclusions

Dengue force-of-infection in India is comparable to other highly endemic countries. Significant variation across sites exists, likely reflecting local epidemiological variation. The number of annual primary infections is indicative of a significant, under-reported burden of secondary infections and symptomatic episodes.

Trial registration

Registered retrospectively with clinicaltrials.gov (NCT01477671; 18/11/2011) and clinical trials registry of India (ctri.nic.in; CTRI/2011/12/002243; 15/12/2011). Date of enrollment of 1st subject: 22/9/2011.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7432-7) contains supplementary material, which is available to authorized users.

A study of hepatitis A virus seropositivity among children aged between 1 and 5 years of age: Implications for universal immunization

Background

Hepatitis A virus (HAV) causes an enterically transmitted viral disease mainly affecting children and endemic in many developing countries, including India. There is an epidemiological shift with an increased incidence of symptomatic cases among children. This study was conducted to assess the seroprevalence of HAV among young children aged below 5 years and the need for universal immunization.

Method

This cross-sectional study was conducted at two tertiary care hospitals in Northern India, from Apr 2014 to Jul 2015, among healthy children aged between 1 and 5 years. The sample size was calculated based on the prevalence of HAV seropositivity of 40% among children aged <10 years [16-60%] and alpha error of 5%. Analysis of serum IgG against HAV was performed by enzyme-linked immunosorbent assay method, and results were analyzed.

Results

A total of 1084 children aged between 12 and 60 months were enrolled, with male-to-female ratio of 1.86:1. A total of 471 children (43.5%) were found to be positive for IgG against HAV. The seroprevalence of HAV was lower among younger children aged 12-23 months (odds ratio [OR] = 0.73, 95% confidence interval [CI] = 0.52-0.87, p = 0.03), which was statistically significant. Seropositivity of HAV was lower among boys and families consuming safe drinking water and having improved sanitation facilities.

Conclusion

The study observed lower seropositivity against HAV among younger children, making them susceptible of contracting the disease. Possible underlying risk factors were younger age, unsafe drinking water, poor sanitation, and low education status of parents. Therefore, vaccination may be recommended as optional vaccine at one year of age, along with improved public health efforts for safe drinking water, hygiene practices, and food safety.

Seroprevalence of Histoplasmosis in Somali, Burmese, and Hmong Refugees Residing in Thailand and Kenya

Histoplasmosis is known to be endemic to the Midwestern United States, but cases have been reported throughout much of the world. Somali, Hmong, and Burmese (ethnically Karen) persons make up some of the largest refugee populations coming the United States in recent years. Yet, information about risk of Histoplasma capsulatum infection amongst these populations is limited. This study used the CDC Migrant Serum Bank to test ~100 samples from each of Somali, Burmese, and Hmong U.S.-bound refugees. Samples were tested by enzyme immunoassay for Histoplasma capsulatum IgG. Overall 1% (2/299) of refugee serum samples were positive for H. capsulatum IgG. One of 99 samples obtained from Hmong refugees was positive, and the other positive sample came from among 100 Burmese refugee samples. H capsulatum IgG positivity was detected at low levels in Hmong and Burmese refugees. No IgG positivity was detected among 100 Somali refugees.

Mucosal and cutaneous Human Papillomavirus seroprevalence among adults in the prevaccine era in Germany - Results from a nationwide population-based survey

BACKGROUND

Human Papillomavirus (HPV) vaccination of girls was introduced in Germany in 2007. However, data on the distribution of vaccine-relevant HPV types in the general population in Germany in the prevaccine era are limited.

METHODS

Serum samples collected during the German National Health Interview and Examination Survey 1998 (GNHIES98), a nationally representative study including men and women aged 18-79 years, were tested for antibodies to 19 mucosal and cutaneous HPV types. Multivariable regression models were developed to identify associations between demographic and behavioral characteristics and HPV seropositivity.

RESULTS

Of the 6517 serum samples tested, almost a quarter was seropositive for at least one of the nine HPV vaccine types with no clear age-pattern. HPV-6 and HPV-59 were the most common mucosal types, while HPV-1 and HPV-4 were the most common cutaneous HPV types. Factors independently associated with HPV-16 seroprevalence were seropositive to other sexually transmitted infections and lifetime number of sex partners, as well as urbanity (only among females).

CONCLUSIONS

Prevalence of naturally acquired antibodies to HPV types which can be prevented by vaccination is high in both sexes and all age groups. These data can serve as baseline estimates to evaluate the population-level impact of the current vaccination strategy.

Sero Conversion of Viral Hepatitis among End Stage Renal Disease Patients on Hemodialysis in Kashmir: Results of a Prospective Study

BACKGROUND

The seroconversion is a significant health concern in patients with end-stage renal disease undergoing hemodialysis particularly in high endemic zones of HBV and HCV.

PATIENTS AND METHODS

This prospective study was conducted from January 2009 to April 2018 at Sheri Kashmir Institute of Medical Sciences, Srinagar, Kashmir. A cohort of 459 end-stage renal disease patients on hemodialysis was enrolled from four dialysis centres and followed in a longitudinal manner. Their seroconversion rates, risk factors were studied. Positive patients were treated and followed up.

RESULTS

This study demonstrated HBV seroconversion rate of 7.4 % (n = 34) and HCV seroconversion rate of 10% (n = 46) in a cohort of 459 patients on hemodialysis attending four dialysis centres of Kashmir. Patients with diabetes mellitus outnumbered in seroconversion rates of (43.75%) followed by patients with glomerulonephritis (23.75%). Of 15 patients who had undergone renal transplantation 10 (66.67%), patients had seroconversion on hemodialysis which was statistically significant (P < 0.001). Patients who were dialysed at multiple HD centres had significant seroconversion than those who followed up at a single center. Seroconversion was associated with longer duration of dialysis (80.30 ± 30.92 vs 61 ± 9.41months, P < 0.000). HBV vaccination of the ESRD patient on hemodialysis was significantly protective against seroconversion (P = 0.000).

CONCLUSIONS

Hepatitis B vaccination, stringent precautions in all dialysis centres could help to reduce the high seroconversion rates which have a high financial burden on ESRD patients. Intense health education to both patients and medical staff will be beneficial to lower the seroconversion rates.

Leptospirosis and Workplace Environmental Risk Factors among Cattle Farmers in Northeastern Malaysia

BACKGROUND

Leptospirosis is an emerging zoonosis and its occurrence has been reported to be rising globally. The environment plays an important role in the survival of Leptospira and determines the risk of infection. Those who were exposed to and had contact with contaminated environment through their occupational, recreational and other activities can be infected with the organism.

OBJECTIVE

To determine the seroprevalence of leptospirosis among cattle farmers, prevalence of pathogenic Leptospira, and the workplace environmental risk factors for leptospirosis among cattle farmers in northeastern Malaysia.

METHODS

A cross-sectional study involving 120 cattle farmers was conducted. The participants answered an interviewer-guided questionnaire that consisted of sociodemographic and workplace environment characteristics questionnaire, before having their blood sample taken for microscopic agglutination test (MAT). Seropositivity was determined using a cut-off titer of ≥1:100. 248 environmental samples were also collected from the cattle farms for polymerase chain reaction (PCR).

RESULTS

The overall seroprevalence of leptospiral antibodies was 72.5% (95% CI 63.5% to 80.1%) and the prevalence of pathogenic Leptospira in the cattle farms environment was 12.1% (95% CI 8.4% to 17.0%). The independent factors associated with seropositivity of leptospirosis among cattle farmers were positive pathogenic Leptospira in the environment (Adj OR 5.90, 95% CI 1.34 to 26.01) and presence of garbage dumping in the farm (Adj OR 2.40, 95% CI 1.02 to 5.65).

CONCLUSION

Preventing leptospirosis incidence among cattle farmers necessitates changes in work environment. Identifying modifiable factors may also contribute to the reduction of infection.

Seroprevalence and risk factors of recent infection with hepatitis E virus during an acute outbreak in an urban setting in Chad, 2017

BACKGROUND

From September 2016-April 2017, Am Timan, Chad, experienced a large HEV outbreak in an urban setting with a limited impact in terms of morbidity and mortality. To better understand HEV epidemiology in this context, we estimated the seroprevalence of anti-HEV antibodies (IgM and IgG) and assessed the risk factors for recent HEV infections (positive anti-HEV IgM) during this outbreak.

METHODS

A serological survey using simple random sampling was implemented in Am Timan at the tail-end of the outbreak (sample size aim = 384 household). Household members provided us with blood samples and household heads answered questions around water, sanitation and hygiene practices and animal ownership. Blood samples were tested for HEV IgG and IgM antibodies using Enzyme-Immune-Assay (EIA). We calculated weighted prevalence estimates and prevalence ratios (PRs) for possible risk factors for recent infection using multivariate Cox regression.

RESULTS

We included 241 households (1529 participants). IgM prevalence decreased with age: 12.6% (< 5 years) to 4.3% (> 15 years). IgG prevalence increased with age: 23.5% (< 5 years) to 75.9% (> 15 years). Risk factors for recent HEV infections included: sharing the sanitation facility with other HHs (PR 1.72; 95%CI: 1.08-2.73), not systematically using soap for HW (PR 1.85; 95%CI: 1.30-2.63) and having animals sleeping inside the compound (PR 1.69; 95%CI: 1.15-2.50).

CONCLUSIONS

Evidence suggests that Am Timan was already highly endemic for HEV before the outbreak, potentially explaining the limited extent of the outbreak. Recent infection with HEV was linked to household level exposures. Future HEV outbreak response must include ensuring access to safe water, and reducing household level transmission through active hygiene and sanitation promotion activities.

Hepatitis C virus seroprevalence and prevalence of chronic infection in the adult population in Ireland: a study of residual sera, April 2014 to February 2016

Robust data on hepatitis C virus (HCV) population prevalence are essential to inform national HCV services. In 2016, we undertook a survey to estimate HCV prevalence among the adult population in Ireland. We used anonymised residual sera available at the National Virus Reference Laboratory. We selected a random sample comprising persons ≥ 18 years with probability proportional to the general population age-sex distribution. Anti-HCV and HCV Ag were determined using the Architect anti-HCV and HCV Ag assays. Fifty-three of 3,795 specimens were seropositive (age-sex-area weighted seroprevalence 0.98% (95% confidence interval (CI): 0.73–1.3%)). Thirty-three specimens were HCV-antigen and antibody-positive (age-sex-area weighted prevalence of chronic infection 0.57% (95% CI: 0.40–0.81%)). The prevalence of chronic infection was higher in men (0.91%; 95% CI: 0.61–1.4%), in specimens from the east of the country (1.4%; 95%CI: 0.99–2.0%), and among persons aged 30–39 years and 40–49 years (1.1% (95% CI: 0.59–2.0%) and 1.1% (95% CI: 0.64–1.9%) respectively). Ireland ranks at the lower end of the spectrum of prevalence of chronic HCV infection internationally. Men born between 1965 and 1984 from the east of the country have the highest rate of chronic HCV infection.

Estimation of expected dengue seroprevalence from passive epidemiological surveillance systems in selected areas of Argentina: A proxy to evaluate the applicability of dengue vaccination

BACKGROUND

Current recommendations about dengue vaccination by the World Health Organization depend on seroprevalence levels and serological status in populations and individuals. However, seroprevalence estimation may be difficult due to a diversity of factors. Thus, estimation through models using data from epidemiological surveillance systems could be an alternative procedure to achieve this goal.

OBJECTIVE

To estimate the expected dengue seroprevalence in children of selected areas in Argentina, using a simple model based on data from passive epidemiological surveillance systems.

METHODS

A Markov model using a simulated cohort of individuals from age 0 to 9 years was developed. Parameters regarding the reported annual incidence of dengue, proportion of inapparent cases, and expansion factors for outpatient and hospitalized cases were considered as transition probabilities. The proportion of immune population at 9 years of age was taken as a proxy of the expected seroprevalence, considering this age as targeted for vaccination. The model was used to evaluate the expected seroprevalence in Misiones and Salta provinces and in Buenos Aires city, three settings showing different climatic favorability for dengue.

RESULTS

The estimates of the seroprevalence for the group of 9-year-old children for Misiones was 79% (95%CI:46-100%), and for Salta 22% (95%CI:14-30%), both located in northeastern and northwestern Argentina, respectively. Buenos Aires city, from central Argentina, showed a likely seroprevalence of 7% (95%CI: 3-11%). According to the deterministic sensitivity analyses, the parameter showing the highest influence on these results was the probability of inapparent cases.

CONCLUSIONS

This model allowed the estimation of dengue seroprevalence in settings where this information is not available. Particularly for Misiones, the expected seroprevalence was higher than 70% in a wide range of scenarios, thus in this province a vaccination strategy directed to seropositive children of >9 years should be analyzed, including further considerations as safety, cost-effectiveness, and budget impact.

Seroprotection against Vaccine-Preventable Diseases amongst Health Care Workers in a Community Hospital, Qatar

Background:

Health care workers (HCW) are at high risk of contracting various infectious diseases and play a dual role in the transmission of infections in health care facilities.

Objective:

To determine the seroprotection against hepatitis B, measles, rubella, and varicella among HCWs in a community hospital in Qatar.

Methods:

This is a cross-sectional survey conducted in a 75-bed community hospital in Dukhan, Qatar. From August 2012 to December 2015, 705 HCWs were tested for the presence of IgG antibodies for measles, rubella, and varicella, and also for hepatitis B surface antigen (HBsAg). They were also asked about previous history of hepatitis B vaccination.

Results:

595 (84.4%) HCWs received a full hepatitis B vaccination schedule; 110 (15.6%) received a single dose. The full schedule was reported with higher frequency by nurses (90.2%) compared to physicians (74.1%) or technicians (79.7%). Those aged ≥30 years (90.4%) and <20 years of work experience had received a full vaccination schedule more frequently than younger and less experienced HCWs. Female HCWs (87.8%) received full schedule more frequently than males (78.8%). 73.4% of the staff had seroprotection against heaptitis B, with the lowest anti-HBsAg titers observed in physicians (58.8%) compared with other categories; males (64.9%) were less protected than females. The seropositivity was 85.6%(95% CI 82.4% to 88.4%) for measles, 94.7% (95% CI 92.2% to 97.3%) for rubella, and 92.2% (95% CI 89.7% to 94.7%) for varicella.

Conclusion:

HCWs, particularly physicians, are not enough protected against hepatitis B. The seroprotection against measles, rubella, and varicella.

[A sero-epidemiological study of hepatitis E among general population in Shandong Province of China in 2014]

Objective: To analyze the sero-epidemiological characteristics of hepatitis E virus (HEV) in Shandong province, and thereby to provide evidence for the policy-making of hepatitis E prevention and control. Methods: The inhabitants aged between 1-59 years old were randomly selected to participate in the study by two-stage stratified random sampling method from 12 counties in Shandong province in October, 2014. Firstly two townships were selected from each county by probability proportional to size sampling (PPS) method. A total of 5 229 participants aged 1-59 years old were selected by stratified random sampling method. All the participants finished a questionnaire survey and a venous blood sample (3-5 ml) was collected from each to test anti-HEV IgG by enzyme-linked assay (ELISA). The weighted prevalence of anti-HEV IgG with different demographic characteristics was estimated. The variance of the positive rate of anti-HEV IgG was calculated by Taylor series linearization method, as well as its 95%CI. A statistical test was conducted to compare the rate of its 95%CI, and the results in the present study were compared with those in sero-survey in 2006. Results: A total of 5 229 subjects entered the final analysis in 2014. The overall weighed prevalence of anti-HEV IgG was 9.19% (95%CI: 6.18%-12.20%) among natural population in Shandong province, decreased by 19.88% in comparison with that in 2006 sero-survey (11.47%, 95%CI: 8.92%-14.02%). The prevalence increased with age increasing (χ(2trend)=288.11, P<0.001) in 2014, which was similar to the result in 2006 sero-survey. Except for 1-4 years old group, the prevalence of anti-HEV IgG in the other age groups were lower than it in the corresponding groups in 2006. The prevalence of anti-HEV IgG in urban (8.19%, 95%CI: 0.00-22.23%), rural areas (9.69%, 95%CI: 4.99%-14.38%), eastern areas (12.70%, 95%CI: 0.00-27.72%), central areas (4.74%, 95%CI: 0.00-9.91%) and western areas (9.32%, 95%CI: 0.69%-17.94%) in 2014 were all lower than the corresponding prevalences (11.39%, 95%CI: 8.17%-14.62%; 11.92%, 95%CI: 8.75%-15.08%; 22.77%, 95%CI: 14.99%-30.55%; 7.97%, 95%CI: 4.75%-11.20%; 10.59%, 95%CI: 6.37%-14.82%) in 2006 survey. The prevalence of anti-HEV IgG in coastal areas (16.56%, 95%CI: 12.94%-20.18%) and inland areas (7.63%, 95%CI: 5.16%-10.10%) in 2014 were lower than it in the corresponding areas (28.04%, 95%CI: 20.45%-35.64%; 9.50%, 95%CI: 7.31%-11.70%) in 2006 survey. The prevalence among peasant (11.98%, 95%CI: 8.20%-15.76%), worker (9.68%, 95%CI: 4.48%-14.88%), cadre (13.90%, 95%CI: 7.47%-20.33%), service provider (12.26%, 95%CI: 1.80%-22.73%) in 2014 survey were lower than it among the corresponding populations (13.76%, 95%CI: 10.15%-17.38%; 21.11%, 95%CI: 12.67%-29.55%; 17.81%, 95%CI: 7.63%-28.00%; 21.08%, 95%CI: 0.03%-42.12%) in 2006 survey. Conclusion: The prevalence of anti-HEV IgG has decreased in Shandong province in the recent years, but the epidemiological characteristics found no obvious changes. HEV susceptibility in natural population was generally high. Hepatitis E vaccines were recommended to be used in HEV high-risk population in the province.

The seroprevalence of Bartonella henselae in healthy adults in Korea

BACKGROUND/AIMS

Cat-scratch disease (CSD), caused by Bartonella henselae is one of the most common zoonosis. However, only several cases of B. henselae infection have been reported in Korea. This study investigated the seroprevalence of B. henselae in healthy adults and related risk factors.

METHODS

Serum samples from 300 healthy participants were analyzed using an immunoglobulin G immunof luorescence assay (IFA) for B. henselae isolated in Korea. Surveys on the risk factors for B. henselae infection were conducted simultaneously.

RESULTS

Of the participants, 47.7% and 15.0% raised dogs and cats, respectively. The overall seroprevalence of B. henselae was 15.0% (IFA titer ≥ 1:64). Participants who had raised cats showed 22.2% seropositivity against B. henselae, and those with no experience with cats showed 13.7% seroprevalence (p = 0.17). Participants who had cats as pets or been scratched by cats, showed 9.8% seropositivity against B. henselae (IFA titer ≥ 1:256). However, those who had not raised or been scratched by a cat showed 2.0% seropositivity (p = 0.015).

CONCLUSIONS

In Korea, the seroprevalence of B. henselae is higher than expected, suggesting that Bartonella infection due to B. henselae is not uncommon. Cats are proposed to play a more important role than dogs in transmission of CSD.

Cross-protection to new drifted influenza A(H3) viruses and prevalence of protective antibodies to seasonal influenza, during 2014 in Portugal

INTRODUCTION

Immune profile for influenza viruses is highly changeable over time. Serological studies can assess the prevalence of influenza, estimate the risk of infection, highlight asymptomatic infection rate and can also provide data on vaccine coverage. The aims of the study were to evaluate pre-existing cross-protection against influenza A(H3) drift viruses and to assess influenza immunity in the Portuguese population.

MATERIALS AND METHODS

We developed a cross-sectional study based on a convenience sample of 626 sera collected during June 2014, covering all age groups, both gender and all administrative health regions of Portugal. Sera antibody titers for seasonal and new A(H3) drift influenza virus were evaluated by hemagglutination inhibition assay (HI). Seroprevalence to each seasonal influenza vaccine strain virus and to the new A(H3) drift circulating strain was estimated by age group, gender and region and compared with seasonal influenza-like illness (ILI) incidence rates before and after the study period.

RESULTS

Our findings suggest that seroprevalences of influenza A(H3) (39.9%; 95% CI: 36.2-43.8) and A(H1)pdm09 (29.7%; 95% CI: 26.3-33.4) antibodies were higher than for influenza B, in line with high ILI incidence rates for A(H3) followed by A(H1)pdm09, during 2013/2014 season. Low pre-existing cross-protection against new A(H3) drift viruses were observed in A(H3) seropositive individuals (46%). Both against influenza A(H1)pdm09 and A(H3) seroprotection was highest in younger than 14-years old. Protective antibodies against influenza B were highest in those older than 65years old, especially for B/Yamagata lineage, 33.3% (95% CI: 25.7-41.9). Women showed a high seroprevalence to influenza, although without statistical significance, when compared to men. A significant decreasing trend in seroprotection from north to south regions of Portugal mainland was observed.

CONCLUSIONS

Our results emphasize that low seroprotection increases the risk of influenza infection in the following winter season. Seroepidemiological studies can inform policy makers on the need for vaccination and additional preventive measures.

Seroprevalence and geographical distribution of human T-lymphotropic virus type 1 among volunteer blood donors in endemic areas of Iran

Background

Human T-cell lymphotrophic virus type 1 (HTLV-1) has a worldwide distribution and it is endemic in some regions of Iran. One of the most important routes of HTLV-1 transmission is via transfusion of contaminated blood components. The risk of transmission through asymptomatic blood donors, particularly in endemic areas should be considered and appropriately managed. The main objective of this study was to determine the seroprevalence and description the geographic distribution of HTLV-1 among voluntary blood donors in Iran.

Methods

This retrospective study carried out using the data obtained from the main database of the seven blood transfusion centers of Iranian Blood Transfusion Organization between 2009 and 2013. The presence of anti-HTLV-1/2 antibodies were primarily assessed using Enzyme-linked Immunosorbent Assay. The Ab Kit assay, contain antigens for the screening of antibodies to HTLV type 1 and 2. So, it is expressed as HTLV 1/2 assay. Samples that were positive by the western blot confirmatory test were considered as definite positive HTLV-1 or HTLV-2 cases. The main socio-demographic variables were; age, gender, donation history and marital status. Descriptive and analytical statistics were used to summarize the gathered data. The chi-Square Statistical test was used to test the association between groups, P-value of less than 0.05 was considered significant.

Results

A total of 1864489 blood donations were evaluated. There were 1840 confirmed HTLV-1 positive donations (0.098%). None were positive for anti-HTLV-2. The overall HTLV-1 prevalence was 98.7 per 100,000 donations during the 5 year period. Seroprevalence was higher among females, married and older blood donors. The overall seropositivity among first time, regular and lapsed donors was, 0.29% (290/100000), 0.001% (1/100000) and 0.02% (20/100000) respectively. A significant difference was observed between regular and the first time (p <0.0001) and also between lapsed and regular blood donors (p <0.0001). Most of the HTLV-1 seropositive blood donors (175 per 100,000) were from northeastern regions. We observed a gradual decline in overall HTLV-1 prevalence during the course of the study, the prevalence rate decreased from 0.13% (130/100000) in 2009 to 0.07% (70/100000) in 2013.

Conclusions

The Seroprevalence of HTLV-1 among Iranian blood donors in the regions of our study still is considerable, but there is an obvious declining prevalence over the course of present study. Blood transfusion centers should continually evaluate the residual risk of infection in the country, especially in endemic areas.

Seroprevalence of Poliovirus Antibodies in the United States Population, 2009-2010

BACKGROUND

Polio is eliminated in the United States, with the last indigenous transmission occurring in 1979. However, global eradication of polio has not yet been completed, so importation of poliovirus into the U.S. is still possible. Specimens from the 2009-10 National Health and Nutrition Examination Survey (NHANES) were analyzed to evaluate population seroprevalence and assess overall risk from a poliovirus importation.

METHODS

We evaluated prevalence of serum antibodies to all three poliovirus types using the National Health and Nutrition Examination Survey during 2009-2010.

RESULTS

The overall seroprevalence to poliovirus was 93.9 % for type 1, 97.0 % for type 2, and 83.1 % for type 3. Seroprevalence was higher for type 2 compared to the other types (p < 0.001) and lower for type 3 compared to the other types (p < 0.001). There was a tendency for higher seroprevalence in the younger age groups, but this varied by serotype.

CONCLUSIONS

Seroprevalence was high (83.1 %-97.0 %) for all three types of poliovirus in the US population during 2009-2010. While there were observed differences by serotype with type 2 having the highest seroprevalence and type 3 having the lowest, consistent with previous observations, no large immunity gaps to poliovirus suggesting an imminent substantial population risk from a poliovirus importation were observed at a population level.

Hepatitis C Seroprevalence and Risk Factors in Adult Population of Chaharmahal and Bakhtiari Province of Iran in 2013

INTRODUCTION

Hepatitis C is the second leading viral infectious disease worldwide. In Iran, hepatitis C is the most important and prevalent reason for chronic hepatitis and liver cirrhosis in the multi transfused population.

AIM

This study was conducted to determine seroprevalence and burden of hepatitis C in Chaharmahal and Bakhtiari province and to plan for controlling it.

MATERIALS AND METHODS

For this analytical, population-based study, 3000 samples were older than 15 years old and were enrolled from urban and rural areas of Chaharmahal and Bakhtiari province, southwest Iran per cluster sampling. Written informed consent was obtained from the participants and the demographic data, transmission route and risk factors were collected after blood sample taking. Hepatitis C virus antibody (HCV Ab) and western blotting were consecutively run.

STATISTICAL ANALYSIS

Data analysis was done by SPSS 19 using descriptive statistics, and chi-square test, Fisher's exact test, and logistic regression Ap value of 0.05 was considered as the level of significance.

RESULTS

The prevalence of HCV Ab was obtained 1.4% (95% CI, 0.95-1.7) and that of positive hepatitis C by western blotting 0.9% (95% CI, 0.65-1.3). The prevalence in men (1.2%) was obtained two times higher than women. The highest prevalence was obtained in 35 to 44-year-old population (2%). The prevalence was higher in married individuals and less in higher educated. History of hospital stay, first degree relatives infected with HCV, jaundice, history of blood transfusion, tattoo, outpatient surgery, imprisonment, contact with the infected, intravenous (IV) drug abuse, and smoking had significant association with disease prevalence (p<0.05). The highest odds ratio was obtained for history of IV drug abuse (OR=38.2, 95% CI, 14.06-103.9) followed by imprisonment (OR=8.9, 95% CI, 2.97-26.6). However, by logistic regression only history of IV drug abuse was obtained as significant (p<0.05).

CONCLUSION

Hepatitis C is growing and emerging as the most prevalent chronic, viral hepatic disease, so further consideration of risk factors and routes of transmission is crucial for appropriate planning for, and preventing, treating, and controlling hepatitis C. IV drug abusers as the most important group need special consideration and surveillance in order to cut infection chain and decrease the disease incidence.

Serological survey of Bartonella spp., Borrelia burgdorferi, Brucella spp., Coxiella burnetii, Francisella tularensis, Leptospira spp., Echinococcus, Hanta-, TBE- and XMR-virus infection in employees of two forestry enterprises in North Rhine-Westphalia, Germany, 2011-2013

We initiated a survey to collect basic data on the frequency and regional distribution of various zoonoses in 722 employees of forestry enterprises in the German state of North Rhine-Westphalia (NRW) from 2011 to 2013. Exposures associated with seropositivity were identified to give insight into the possible risk factors for infection with each pathogen. 41.2% of participants were found to be seropositive for anti-Bartonella IgG, 30.6% for anti-Borrelia burgdorferi IgG, 14.2% for anti-Leptospira IgG, 6.5% for anti-Coxiella burnetii IgG, 6.0% for anti-Hantavirus IgG, 4.0% for anti-Francisella tularensis IgG, 3.4% for anti-TBE-virus IgG, 1.7% for anti-Echinococcus IgG, 0.0% for anti-Brucella IgG and anti-XMRV IgG. Participants seropositive for B. burgdorferi were 3.96 times more likely to be professional forestry workers (univariable analysis: OR 3.96; 95% CI 2.60-6.04; p<0.001); and participants seropositive for Hantavirus 3.72 times more likely (univariable analysis: OR 3.72; 95% CI 1.44-9.57; p=0.007). This study found a surprisingly high percentage of participants seropositive for anti-B. henselae IgG and for anti-F. tularensis IgG. The relatively high seroprevalence for anti-Leptospira IgG seen in this study could be related to living conditions rather than to exposure at work. No specific risk for exposure to C. burnetii and Echinococcus was identified, indicating that neither forestry workers nor office workers represent a risk population and that NRW is not a typical endemic area. Forestry workers appear to have higher risk for contact with B. burgdorferi-infected ticks and a regionally diverse risk for acquiring Hantavirus-infection. The regional epidemiology of zoonoses is without question of great importance for public health. Knowledge of the regional risk factors facilitates the development of efficient prevention strategies and the implementation of such prevention measures in a sustainable manner.

Prevalence of syphilis, human immunodeficiency virus, hepatitis B virus, and human T-lymphotropic virus infections and coinfections during prenatal screening in an urban Northeastern Brazilian population

OBJECTIVES

To evaluate prevalences of Treponema pallidum, human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV), and hepatitis B virus (HBV) infections and coinfections during prenatal screening in an urban Northeastern Brazilian population through a large dataset.

METHODS

Secondary data were obtained from the Maceió (Alagoas, Brazil) municipal prenatal screening program from June 2007 to May 2012. Dried blood serum tests from 54,813 pregnant women were examined to determine prevalences of T. pallidum, HIV, HTLV, and HBV infections and coinfections, and the seroconversion rates for syphilis and HIV infection. Socio-demographic variables associated with syphilis and HIV infection were identified.

RESULTS

The prevalences of syphilis, HIV, HTLV, and HBV infections were 2.8%, 0.3%, 0.2%, and 0.4%, respectively. Pregnant women infected with T. pallidum had a 4.62-fold greater risk of HIV coinfection, and pregnant women infected with HIV had a 5.71-fold greater risk of T. pallidum coinfection. Seroconversion for syphilis and HIV during pregnancy occurred in 0.5% and 0.06% of women, respectively. Among the women carrying HTLV, 4.2% also had an HBV infection.

CONCLUSIONS

Syphilis was twice as prevalent among pregnant women in Maceió, compared to the national average, and coinfections with syphilis/HIV and HTLV/HBV were significantly associated among these pregnant women.