Comparison of varicella history with presence of varicella antibody in refugees

Cross sectional survey of Varicella-Zoster virus and measles seropositivity in people living with HIV in a Parisian suburb and a review of current immunization guidelines

According to evidence-based guidelines, vaccines against measles and varicella are generally recommended to susceptible HIV-positive patients, as long as they are not severely immunocompromised. However, routine screening to determine serologic status is not recommended. We conducted a seroprevalence study of anti-measles and anti-Varicella-Zoster virus (VZV) antibodies in adults living with HIV (PLWHA) consulting at Avicenne University Hospital in a Parisian suburb. Sera were collected in years 2018-2020 and tested by commercial immunoassays in 268 patients. Most of the patients were born in Sub-Saharan Africa (55 %) and only 23 % in Europe. Measles and varicella seropositivity were present respectively in 91.4 % and 96.2 % of patients. One patient in ten was seronegative to at least one of tested diseases. In the univariate analysis, only younger age (p = 0.027) was associated with a higher risk of measles seronegativity, while shorter time since arrival in France (p < 0.001) and shorter time since HIV discovery (p = 0.007) were associated with a higher risk of VZV seronegativity. In multivariate analysis no association was found. This study highlights the absence of specific risk factors for VZV and measles seronegativity in PLWHA and supports the importance of routine screening, in order to increase immunization rates and reduce risk of complications.

Concordance of self-reported varicella history and serology among adolescent and adult refugee patients at a primary care clinic in Toronto, Canada

BACKGROUND

Previous studies have found higher rates of varicella susceptibility among migrants from tropical regions. This study seeks to estimate the prevalence of varicella susceptibility in a cohort of newly arrived refugees and refugee claimants at a primary care clinic in Toronto and to compare patients' self-reported history of varicella infection with serologic test results.

METHODS

We conducted a retrospective chart review of 1888 refugee patients aged 13 years and older rostered at a specialized primary care clinic in Toronto from December 2011 to October 2017. Basic sociodemographic variables, self-reported varicella history, and varicella serologic results were examined.

RESULTS

Based on serologic testing, 8.5% of individuals were varicella non-immune, with highest rates of varicella susceptibility among adolescents aged 13-19 years (13.5%). All adults over age 60 were varicella immune on serology (n = 56). A positive self-reported history of varicella infection was strongly predictive of varicella immunity on serology (PPV 96.8%; 95% CI: 95.2-97.9). A self-reported history of no prior varicella infection did not correlate reliably with serologic test results (NPV 15.8%; 95% CI: 13.3-18.0). A substantial proportion of patients (34.1%) were unsure of their varicella history.

CONCLUSION

Identification and immunization of varicella susceptible refugee newcomers remains a health care priority. Self-reported history of varicella infection had mixed reliability as a predictor of varicella immunity.

Epidemiology of varicella among immigrants and non-immigrants in Quebec, Canada, before and after the introduction of childhood varicella vaccination: a retrospective cohort study

BACKGROUND

Many immigrants are susceptible to varicella on arrival to Canada because of different transmission dynamics in their countries of origin and scarcity of vaccination. Universal childhood vaccination programmes decrease varicella incidence rates through herd immunity, but the accumulating number of susceptible adult immigrants could remain at risk for severe varicella. Our aim was to describe the epidemiology of varicella among immigrants and non-immigrants before and after childhood varicella vaccination.

METHODS

We did a population-based, retrospective cohort study of all varicella cases in Quebec, Canada, diagnosed between 1996 and 2014 in administrative health databases linked to immigration data. Cases of varicella met diagnostic codes in the International Classification of Diseases, Ninth and Tenth Revision Canadian modifications. Cases with a co-occurring zoster diagnostic code and immigrants from Australia, New Zealand, the USA, and western European countries were excluded. Vaccination periods included pre-vaccination (1996-98), private vaccination (1999-2005), and public vaccination (2006-14). Incidence rate and comparative rate ratios were estimated using census data.

FINDINGS

A total of 231 339 varicella cases diagnosed between Jan 1, 1996, and Dec 31, 2014, were linked to 1 115 696 immigrants who arrived between Jan 1, 1980, and Dec 31, 2014. 1444 herpes zoster cases and 1276 immigrants from Australia, western Europe, New Zealand, and the USA were excluded. Among 228 619 varicella cases, 13 315 (5·8%) occurred in immigrants. In pre-vaccination versus public vaccination periods, varicella incidence declined in immigrants by 87% (95% CI 86·6-87·9; 324·3 cases per 100 000 person-years to 40·9 cases per 100 000 person-years) and in non-immigrants by 93% (92·4-92·7; 484 cases per 100 000 person-years to 36 cases per 100 000 person-years). Mean age at diagnosis increased in both groups (15·1 vs 19·4 years in immigrants and 8·4 vs 12·0 years in non-immigrants). In the public vaccination period, immigrants younger than 50 years had higher varicella rates than non-immigrants, with relative risk ranging from 1·53 (95% CI 1·37-1·72) to 4·64 (3·90-5·53) with the highest risk in adolescents and young adults, and people from Latin America and the Caribbean (age-specific incidence rate ratio [aIRR]_I-NI pre-vaccination 2·19 and post-vaccination aIRR_I-NI6·07) and south Asia (aIRR_I-NI pre-vaccination 3·41 and aIRR_I-NI post-vaccination 4·46) and in childbearing women (15-40 years; IRR_I-NI 2·48).

INTERPRETATION

Immigrant adolescents, young adults, and women of childbearing age had higher age-standardised rates of varicella than non-immigrants, with increasing disparities following vaccine introduction. Immigrants younger than 50 years of age would benefit from targeted vaccination upon arrival to host countries.

FUNDING

The Canadian Institutes of Health Research and The Department of Medicine, Jewish General Hospital, Montreal, QC, Canada.

Infectious diseases in post-trial detention and comparisons with pre-trial detention: A study in Geneva, Switzerland

BACKGROUND

Prevalence rates of infectious diseases in post-trial prisons have been scarcely investigated. Due to the specific characteristics of these prison populations, these prevalence rates may differ from pre-trial prisons and more information is needed for developing adequate prevention and treatment interventions. This study compared prevalence rates of hepatitis B virus (HBV), hepatitis C virus (HCV), susceptibility to varicella zoster virus (VZV) and measles in pre- and post-trial detention.

METHODS

Data were collected in Geneva post-trial prisons among males (n=250), including serological tests, demographics, and risk factors, and were compared to those of the Geneva pre-trial prison (n=273).

RESULTS AND CONCLUSIONS

Incarcerated men in post-trial detention shared a disproportionate burden of infectious diseases compared to community (chronic HBV: 5.9%, HVC: 2.8%, susceptibility to VZV: 5.9%, to measles: 4.7%). Susceptibility to VZV and prevalence rate of HCV were lower in post-trial prisons (p=.034 and p=.080). Prevalence rates of infectious diseases in prison should be interpreted in light of the prison population's characteristics. Screening and treatment should be promoted in all types of prison settings. Since overcrowding and turnover of pre-trial prisons restrict the access to screening, prevention and treatment of infectious diseases, interventions are crucial in post-trial prisons.

An outbreak of chickenpox in an asylum seeker centre in Italy: outbreak investigation and validity of reported chickenpox history, December 2015-May 2016

An outbreak of chickenpox occurred between December 2015 and May 2016 among asylum seekers in a reception centre in Latium, Italy. We describe the epidemiological and laboratory investigations, control measures and validity of reported history of chickenpox infection. Serological screening of all residents and incoming asylum seekers was performed, followed by vaccine offer to all susceptible individuals without contraindication. Forty-six cases were found and 41 were associated with the outbreak. No complications, hospitalisations or deaths occurred. Serological testing was performed in 1,278 individuals and 169 were found to be susceptible, with a seroprevalence of 86.8%. A questionnaire was administered to 336 individuals consecutively attending the CARA health post to collect their serological result. The sensitivity, specificity and the positive and negative predictive value (PPV and NPV) of the reported history of chickenpox were 45.0%, 76.1%, 88.3% and 25.6%, respectively. We observed an increasing trend for the PPV and decreasing trend for the NPV with increasing age. Our report confirms that, in the asylum seeker population, chickenpox history is not the optimal method to identify susceptible individuals. Our experience supports the need for additional prevention and control measures and highlights the importance of national and local surveillance systems for reception centres.

Varicella zoster virus transmission in youth during incarceration

Purpose - Facility-based Varicella zoster virus (VZV) transmission is reported in a Canadian youth offender correctional centre (YOCC). Transmission occurred from an immunocompetent youth offender (YO) with localized Herpes zoster to another immunocompetent single dose vaccinated YO, resulting in Varicella zoster (VZ) breakthrough disease. The purpose of this paper is to identify infection prevention and control (IPAC) measures utilized in this setting. Design/methodology/approach - A retrospective chart and immunization record review was conducted for two VZV cases and 27 exposed YO contacts in order to obtain demographic, clinical and immunization data. Descriptive data analysis was performed. Findings - All VZV cases and exposed contacts were male with an average age of 14.2 and 15.6 years for cases and contacts, respectively. Both cases shared the same living unit in the YOCC. There were 28 identified YO contacts, of whom 70 percent were single dose vaccinated with univalent vaccine, followed by 22 percent with a previous history of Varicella disease. All cases and contacts were born in Canada. No foreign-born populations were involved with this event. Infection control measures included additional precaution management, enhanced surveillance and environmental cleaning. As such, no hospitalizations or post-exposure immunizations were required. Originality/value - This report highlights the role that VZ breakthrough disease could play in fueling an outbreak in a high-risk environment without rapid recognition and implementation of preventative measures. It also underscores the importance of IPAC presence and public health immunization programs within correctional centers to avoid infectious disease threats.

Serological Susceptibility to Varicella Among U.S. Immigration and Customs Enforcement Detainees

U.S. Immigration and Customs Enforcement (ICE) is responsible for detaining unauthorized aliens during immigration proceedings. During 2014 to 2015, adult ICE detainees at a California facility were invited to complete a survey concerning self-reported varicella history and risk factors. Participants underwent serological testing for varicella-zoster virus (VZV) IgG; susceptible individuals were offered varicella vaccination. Among 400 detainees with available serology results, 48 (12%) were susceptible to varicella. Self-reported varicella history was negatively associated with susceptibility (adjusted odds ratio = 0.16; 95% confidence interval [0.07, 0.35]). Among 196 detainees reporting a positive history, 95% had VZV IgG levels suggestive of varicella immunity. Among 44 susceptible detainees offered vaccination, 86% accepted. Given relatively high varicella susceptibility, targeted screening and vaccination among ICE detainees lacking a positive history might reduce varicella transmission risks.

Vaccination in newly arrived immigrants to the European Union

The challenge of assimilating millions of immigrants in the European region each year presents significant socioeconomic issues. Among them is the threat of vaccine preventable diseases (VPDs) disease transmission within immigrant groups and the broader population given the permeability of nation state borders. A total of 3.8 million people immigrated to the European Union (EU) in 2014, among those were 1.6 million non-EU nationals. While vaccines have markedly reduced the transmission of disease, clusters of under-vaccinated individuals potentiate the rapid transmission of once-eradicated or controlled diseases. Immigrants pose a special challenge to host country public health vaccination programmes. Wars in their native countries may have interrupted vaccination programmes, documentation may be unavailable or unreliable, and refugees may present with health issues due to poor sanitation and food during transit. Further, immigrants are often reticent to access health care in the destination country, or may face financial or language barriers. Thus, preventive health care needs may go unaddressed and the first contact with a clinician is for an emergency. Equitable access to acute and preventive health care and services, including immunizations irrespective of individual's immigration status, should be a priority for European region countries. Ensuring appropriate and timely vaccination for immigrants could be accomplished with a universal European region immunization schedule. Priority should be given to highly communicable VPDs such as measles, mumps, rubella, pertussis, diphtheria, varicella and polio.

Seroprevalence of varicella-zoster virus in five US-bound refugee populations

Little is known about varicella-zoster virus (VZV) susceptibility in US-bound refugee populations, although published data suggest that VZV seroprevalence in these refugee populations may be lower than US populations. We describe VZV seroprevalence in five US-bound refugee groups: (1) Bhutanese in Nepal, (2) Burmese on the Thailand-Burma (Myanmar) border, (3) Burmese in Malaysia, (4) Iraqi in Jordan, and (5) Somali in Kenya. Sera were tested for presence of VZV IgG antibodies among adults aged 18-45 years. Overall VZV seroprevalence was 97% across all refugee groups. VZV seroprevalence was also high across all age groups, with seroprevalence ranging from 92-100% for 18-26 year-olds depending on refugee group and 93-100% for 27-45 year-olds. VZV seroprevalence was unexpectedly high in these five US-bound refugee groups, though may not reflect seroprevalence in other refugee groups. Additional studies are needed to better understand VZV seroprevalence in refugee populations over time and by region.

Application of Oral Fluid Assays in Support of Mumps, Rubella and Varicella Control Programs

Detection of specific viral antibody or nucleic acid produced by infection or immunization, using oral fluid samples, offers increased potential for wider population uptake compared to blood sampling. This methodology is well established for the control of HIV and measles infections, but can also be applied to the control of other vaccine preventable infections, and this review describes the application of oral fluid assays in support of mumps, rubella and varicella national immunization programs. In England and Wales individuals with suspected mumps or rubella, based on clinical presentation, can have an oral fluid swab sample taken for case confirmation. Universal varicella immunization of children has led to a drastic reduction of chickenpox in those countries where it is used; however, in England and Wales such a policy has not been instigated. Consequently, in England and Wales most children have had chickenpox by age 10 years; however, small, but significant, numbers of adults remain susceptible. Targeted varicella zoster virus (VZV) immunization of susceptible adolescents offers the potential to reduce the pool of susceptible adults and oral fluid determination of VZV immunity in adolescents is a potential means of identifying susceptible individuals in need of VZV vaccination. The main application of oral fluid testing is in those circumstances where blood sampling is deemed not necessary, or is undesirable, and when the documented sensitivity and specificity of the oral fluid assay methodology to be used is considered sufficient for the purpose intended.

Assessing adherence to accepted national guidelines for immigrant and refugee screening and vaccines in an urban primary care practice: a retrospective chart review

In the United States, 38.5 million people are foreign-born, one in three arriving since 2000. Health issues include high rates of hepatitis B, humanimmunodeficiency virus infection, parasitic infections, and M. tuberculosis. We sought to determine rates of provider adherence to accepted national guidelines for immigrant and refugee health screening and vaccines done at the primary care clinics at Boston Medical Center. Randomized, retrospective chart review of foreign born patients in the primary care clinics. We found low screening and immunization rates that do not conform to CDC/ACIP guidelines. Only 43 % of immigrant patients had tuberculosis screening, 36 % were screened for HIV and hepatitis B, and 33 % received tetanus vaccinations. Organizational changes incorporating multi-disciplinary approaches such as creative use of nursing staff, protocols, standing orders, EMR reminders, and web based educational tools can contribute to better outcomes by identifying patients and improving utilization of guidelines.

Pathogenesis of varicelloviruses in primates

Varicelloviruses in primates comprise the prototypic human varicella-zoster virus (VZV) and its non-human primate homologue, simian varicella virus (SVV). Both viruses cause varicella as a primary infection, establish latency in ganglionic neurons and reactivate later in life to cause herpes zoster in their respective hosts. VZV is endemic worldwide and, although varicella is usually a benign disease in childhood, VZV reactivation is a significant cause of neurological disease in the elderly and in immunocompromised individuals. The pathogenesis of VZV infection remains ill-defined, mostly due to the species restriction of VZV that impedes studies in experimental animal models. SVV infection of non-human primates parallels virological, clinical, pathological and immunological features of human VZV infection, thereby providing an excellent model to study the pathogenesis of varicella and herpes zoster in its natural host. In this review, we discuss recent studies that provided novel insight in both the virus and host factors involved in the three elementary stages of Varicellovirus infection in primates: primary infection, latency and reactivation.

Use of vaccination in a large outbreak of primary varicella in a detention setting for African immigrants

BACKGROUND

Primary varicella (PV) presents a public health risk for adults in closed residential settings, especially for immigrants from tropical areas where infection during childhood is less likely.

METHODS

In this study, an outbreak of PV at a detention facility for illegal immigrants from Eritrea and Sudan in southern Israel is described. Basic demographic information and clinical course for all cases were obtained.

RESULTS

One hundred and nine cases of PV, all in young adult men aged 18-40 years, were diagnosed over a 7-month period (June to December 2012). Diagnosed patients were placed in quarantine until the resolution of illness without other public health measures being implemented. The Israeli Ministry of Health was notified of the outbreak in early December and recommended two doses of varicella vaccine for all susceptible detainees and staff. Within 2 weeks of completion of the first dose of vaccine, there was only one additional case in a detainee immunized 13 days prior to diagnosis. The effectiveness of vaccination in halting the outbreak was immediate, despite the fact that 15.6% of detainees refused to be immunized.

CONCLUSIONS

The possible roles of vaccination or natural infection in achieving herd immunity and thereby ending the outbreak in this population are discussed. We recommend considering early vaccination for all when an outbreak or a series of connected cases is detected in a closed-residential setting such as the detention facility described here.

Validity of a reported history of chickenpox in targeting varicella vaccination at susceptible adolescents in England

INTRODUCTION

In the UK, primary varicella is usually a mild infection in children, but can cause serious illness in susceptible pregnant women and adults. The UK Joint Committee on Vaccination and Immunisation is considering an adolescent varicella vaccination programme. Cost-effectiveness depends upon identifying susceptibles and minimising vaccine wastage, and chickenpox history is one method to screen for eligibility. To inform this approach, we estimated the proportion of adolescents with varicella antibodies by reported chickenpox history.

METHODS

Recruitment occurred through secondary schools in England from February to September 2012. Parents were asked about their child's history of chickenpox, explicitly setting the context in terms of the implications for vaccination. 247 adolescents, whose parents reported positive (120), negative (77) or uncertain (50) chickenpox history provided oral fluid for varicella zoster virus-specific immunoglobulin-G (VZV-IgG) testing.

RESULTS

109 (90.8% [85.6-96.0%]) adolescents with a positive chickenpox history, 52 (67.5% [57.0-78.1%]) with a negative history and 42 (84.0% [73.7-94.3%]) with an uncertain history had VZV-IgG suggesting prior infection. Combining negative and uncertain histories, 74% had VZV-IgG (best-case). When discounting low total-IgG samples and counting equivocals as positive (worst-case), 84% had VZV-IgG. We also modelled outcomes by varying the negative predictive value (NPV) for the antibody assay, and found 74-87% under the best-case and 84-92% under the worst-case scenario would receive vaccine unnecessarily as NPV falls to 50%.

CONCLUSION

Reported chickenpox history discriminates between varicella immunity and susceptibility in adolescents, but significant vaccine wastage would occur if this approach alone were used to determine vaccine eligibility. A small but important proportion of those with positive chickenpox history would remain susceptible. These data are needed to determine whether reported history, with or without oral fluid testing in those with negative and uncertain history, is sufficiently discriminatory to underpin a cost-effective adolescent varicella vaccination programme.

Seroepidemiology of varicella-zoster virus and reliability of varicella history in Turkish children, adolescents and adults

This study aimed to assess the age specific varicella-zoster virus (VZV) seroprevalence in Izmir, Turkey and to determine the reliability of a history of varicella to detect susceptible children, adolescents and adults. A questionnaire, including previous history of varicella, was completed for each participant and, in 590 of them, VZV-specific IgG was measured using an ELISA test. Overall, 28.5% of individuals were seronegative for VZV. By 5 years of age, only 25.5% of children were seropositive for VZV. Among adolescents and young adults, 18.8% and 11.7% were seronegative, respectively. The negative predictive value was 57.8%, decreasing with age (81.9% in children, 34.5% in adolescents and 8.3% in adults). In conclusion, a negative history of varicella is not a reliable predictor of varicella antibody status in adolescents and young adults. Serological testing before immunisation will be logical, rather than presumptive vaccination, for adolescents and adults with negative history of varicella.

Chickenpox in a Swiss prison: susceptibility, post-exposure vaccination and control measures

After the occurrence of a case of chickenpox in Switzerland's largest pre-trial prison, protective measures including post-exposure vaccination were implemented, as chickenpox can cause severe complications in adults. Serology for chickenpox was carried out for all contacts of the index case and rapid post-exposure vaccination proposed to all prisoners with a negative history for chickenpox. Susceptibility was found in 14 out of 110 prisoners (12.7%; 95% confidence interval 6.5-18.9). The positive predictive value of a history of chickenpox was 90%. In this predominantly migrant population, susceptibility to chickenpox was approximately 6 times higher than in the general Swiss adult population. Since the attack rate among susceptible household contacts is usually high, preventive measures such as vaccination and quarantine probably allowed containment of the spread of infection.

Reliability of information on varicella history in preschool children

OBJECTIVE

To verify how reliable is the information provided by parents about the history of varicella in their children.

METHODS

204 parents of previously healthy children attending two municipal day-care centers of São Paulo city were interviewed between August 2003 and September 2005. A standardized form was filled out with information regarding age, sex, history of varicella and other diseases, drug use and antecedent of immunization, After medical history, physical examination and checking of immunization records, 5 ml of blood were collected for ELISA (in house) varicella test. Exclusion criteria were: age less than 1 year or more than 60 months, previous immunization against chickenpox, presence of co-morbidities or recent use of immunosuppressive drugs. Data were filed in a data bank using the Excel 2003 Microsoft Office Program and stored in a PC computer. The exact Fisher test was employed to calculate sensibility, specificity, positive and negative predictive values of history of varicella informed by children's parents.

RESULTS

The age of the children varied from 12 to 54 months (median, 26 months; 49 (24%) children had positive history of varicella, 155 (76%) a negative or doubtful history. The predictive positive and negative values of the information were 90% and 93%, respectively (p = 0.0001).

CONCLUSIONS

The degree of reliability of information about history of varicella informed by parents of children attending day care centers was high and useful to establish recommendations on varicella blocking immunization in day-care centers.

Seroprevalence of antibody to varicella among Somali refugees

OBJECTIVES

To determine the seroprevalence of varicella antibody among recent Somali refugees living in Olmsted County, Minnesota, and to estimate the risk of varicella-zoster virus (VZV) infection in this group.

SUBJECTS AND METHODS

We obtained blood samples from the study subjects, along with demographic information, immunization records, and vaccine-preventable disease history. Serum samples were tested using a whole-virus IgG VZV-specific commercial enzyme-linked immunosorbent assay kit. This study was completed in 1998.

RESULTS

Overall, 200 Somali refugees, comprising 33 extended families, were interviewed, with 193 providing adequate blood samples. Thirty-five subjects (18%) were seronegative for varicelia. Males had a significantly higher seronegativity rate (25% [n = 23]) compared with females (12% [n = 12]; P = .02); however, this association disappeared after adjustment for age and varicella infection history. Five percent (5/92) of adults were seronegative compared with 30% (30/101) of all children (P < .001). Eight percent (5/61) of the adult females were seronegative, whereas none (0/31) of the adult males were seronegative. Conversely, 38% (23/60) of male children were seronegative compared with 17% (7/41) of female children (P < .001).

CONCLUSION

These results demonstrate a high prevalence of varicella seronegativity among Somali refugees who have immigrated to an endemic area. We recommend instituting improved education regarding varicella among Somali communities and increasing vaccine uptake or routine testing for serum varicella antibody to prevent VZV-related morbidity and mortality, particularly in adolescents, adult refugees, and women of childbearing age.

Immunizations and infectious disease screening for internationally adopted children

Health care professionals play a critical role in providing age-appropriate immunizations and assessing newly arrived internationally adopted children for infectious diseases. A systematic approach to screening for infectious diseases combined with assessment of signs and symptoms that could be related to diseases prevalent in the child's country of origin supports children's long-term health and that of their new families.