Trends in Hospital Admissions for Pertussis Infection: A Nationwide Retrospective Observational Study in Italy, 2002-2016

[Epidemiological profile of pertussis in infants in Casablanca from 2012 to 2019]

Pertussis is a real public health problem due to high neonatal morbidity rates and resurgence despite high vaccination coverage. The purpose of this study is to analyze the epidemiological profile of pertussis in infants hospitalized from 2012 to 2019. We conducted a retrospective, descriptive study over a 7-year and 8-month period from January 2012 to July 2019. It involved 500 infants admitted with clinical suspicion of pertussis. The average age of infants was 72 days, ranging from 28 days to 18 months; 75% of infants were less than 3 months old. The peak incidence was registered in 2012 and 2016, with a summer predominance (32%); 460 infants (92%) were not or incompletely vaccinated, 42.2% of whom were too young to be vaccinated. A probable contaminant in the entourage was found in 43,6% of cases. Whooping cough and cyanosis were the main reason for hospitalization (77.6%). Chest radiography objectified bronchial disease (25,4%) and alveolar foci (22.7%). Blood count performed in 410 infants showed hyperlymphocytosis in 67.5% of cases. Polymerase chain reaction (PCR) on nasopharyngeal sample collected from 206 infants was positive for Bordetella pertussis in 64% of cases; 118 PCR performed in mothers were positive in 47.7% of cases. All infants received Clarithromycin. Pertussis is a major cause of morbidity in infants in Casablanca. The prevention strategy is based on vaccination of family members of infants. However, vaccination of pregnant women appears to be more effective.

Pertussis immunisation strategies to optimise infant pertussis control: A narrative systematic review

OBJECTIVE

Countries routinely offering acellular pertussis vaccine, where long-term protection is not sustained, have the challenge of selecting an optimal schedule to minimise disease among young infants. We conducted a narrative systematic review and synthesis of information to evaluate different pertussis immunisation strategies at controlling pertussis disease, hospitalisation, deaths, and vaccine effectiveness among young infants.

METHODS

We conducted a review of the literature on studies about the primary, booster, and/or maternal vaccination series and synthesised findings narratively. Countries offering the first three doses of vaccine within six-months of life and a booster on or before the second year or life were defined as accelerated primary and booster schedules, respectively. Countries offering primary and booster doses later were defined as extended primary and booster schedules. All search results were screened, and articles reviewed and reconciled, by two authors. The Risk of Bias in Non-randomised Studies of Intervention tool was used to evaluate the risk of bias.

FINDINGS

A total of 98 studies were included in the analyses and the following recurring themes were described: timing of vaccination, vaccine coverage, waning immunity/vaccine effectiveness, direct and indirect effectiveness, switching from an accelerated to extended schedule, impact of changes in testing. The risk of bias was generally low to moderate for most studies.

CONCLUSION

Comparing schedules is challenging and there was insufficient evidence to that one schedule was superior to another. Countries must select a schedule that maintains high vaccine coverage and reduced the risk of delaying the delivery vaccines to protect infants.

Sero-Epidemiological Study of Bordetella pertussis Infection in the Italian General Population

A multicenter study was conducted to estimate the prevalence of pertussis IgG antibodies (anti-PTx) in the Italian population. Serum samples (4154) collected in the years 2019−2020 from subjects aged 6 to 90 years were tested. The anti-PTx IgG levels were determined by ELISA test. The limit of detection was 5 IU/mL (International Units per milliliter); values ≥ 40 IU/mL and ≥100 IU/mL indicate an infection that has occurred in recent years and a recent infection (occurred during the last year), respectively. The mean concentration of anti-PTx IgG antibodies in the tested samples was 13 IU/mL; 1.0% of subjects had a titer ≥ 100 IU/mL, 5.3% a titer between 40 and 100 IU/mL, and 38.9% a titer < 5 IU/mL. The mean antibody concentration was significantly higher in males than in females. The age group 25−39 years had the lowest percentage of negative subjects (36.9%) and the highest prevalence of subjects with antibody titers ≥ 100 IU/mL (1.3%). In the age group ≥ 65 years, the prevalence of subjects with titers between 40 and 100 IU/mL (6.7%) and the percentage of negative subjects (44.8%) was higher than in the other age groups. The results highlight the possible role of adolescents and adults in the transmission of B. pertussis.

Spatiotemporal analysis of pertussis in Hunan Province, China, 2009-2019

OBJECTIVES

This study aims to explore the spatial and spatiotemporal distribution of pertussis in Hunan Province, and provide a scientific basis for targeting preventive measures in areas with a high incidence of pertussis.

DESIGN

In this retrospective spatial and spatiotemporal (ecological) study, the surveillance and population data of Hunan Province from 2009 to 2019 were analysed. The ArcGIS V.10.3 software was used for spatial autocorrelation analysis and visual display, and SaTScan V.9.6 software was used for statistical analysis of spatiotemporal scan data.

SETTINGS

Confirmed and suspected pertussis cases with current addresses in Hunan Province and onset dates between 1 January 2009 and 31 December 2019 were included in the study.

PARTICIPANTS

The study used aggregated data, including 6796 confirmed and suspected pertussis cases.

RESULTS

The seasonal peak occurred between March and September, and scattered children were at high risk. The global Moran's I was between 0.107 and 0.341 (p<0.05), which indicated that the incidence of pertussis in Hunan had a positive spatial autocorrelation. The results of local indicators of spatial autocorrelation analysis showed that the hot spots were mainly distributed in the northeast region of Hunan Province. Moreover, both purely space and spatiotemporal scans showed that the central and northeastern parts were the most likely cluster areas with an epidemic period between March and October in 2018 and 2019.

CONCLUSION

The distribution of the pertussis epidemic in Hunan Province from 2009 to 2019 shows spatiotemporal clustering. The clustering areas of the pertussis epidemic were concentrated in the central and northeastern parts of Hunan Province between March and October 2018 and 2019. In areas with low pertussis incidence, the strengthening of the monitoring system may reduce under-reporting. In areas with high pertussis incidence where we could study whether the genes of endemic pertussis strains are mutated and differ from vaccine strains.

Burden of pertussis among young infants in Malaysia: A hospital-based surveillance study

BACKGROUND

The case fatality rate and the risk of complications due to pertussis is very high in infants. Asia has the second highest childhood pertussis burden. The study aimed to assess the prevalence, clinical complications, and mortality rates of pertussis disease requiring hospitalization among young infants in Malaysia.

METHODS

The study was a one-year, hospital-based, multi-site surveillance of infants less than six months of age with symptoms consistent with pertussis and a cross-sectional analysis of their mothers for recent pertussis infection. Information was obtained from medical records and interviews with the parents. Pertussis diagnosis was confirmed for all infants through serum anti-PT titration test or PCR test.

RESULTS

441 possible cases of pertussis were included in this study. Of these, 12.7 % had laboratory confirmation of pertussis. Infants with confirmed pertussis had significantly higher rates of cyanosis (37.5 % vs 8.6 %; p < 0.0001) and apnea (12.5 % vs 3.9 %; p = 0.027) than test-negative infants. Most infants from both groups were in recovery/recovered at discharge. Those with confirmed pertussis had higher case fatality rate than test-negative cases (5.4 % vs 1.0 %; p = 0.094), but the difference did not reach significance. The majority of confirmed pertussis cases (89.3 %) occurred in infants too young to be fully vaccinated or under-vaccinated for their age. Both test-negative and confirmed pertussis resulted in work-day losses and incurred costs for both parents.

CONCLUSIONS

A high pertussis disease burden persists in infants less than six months of age, especially among those un- and under-vaccinated. Maternal and complete, on-time infant vaccination is important to reduce disease burden.

Severe pertussis disease in a paediatric population: The role of age, vaccination status and prematurity

AIM

To estimate hospitalisation rate and investigate the role of age, prematurity and vaccination status in severe pertussis cases.

METHODS

We retrospectively evaluated 200 children aged 0-14 years, admitted to the emergency rooms of Meyer Hospital of Florence and Pisa Hospital with a diagnosis of pertussis from 1 October 2010 to 31 January 2020.

RESULTS

Children younger than 12 months were 63.0%. Preterm infants were 6.5%. The rate of hospitalisation was 49.0%. Among hospitalised cases, 80.6% were younger than 5 months. Overall, 62.0% were unvaccinated; this percentage increased among hospitalised (73.5%) and preterm subsamples (76.9%). Delays in pertussis vaccination were found in 57.7% of term infants and in 80.0% of preterms. Multivariable analysis confirmed the age under 2 months as the variable at higher risk for hospitalisation (OR 4.49, 95% CI 1.85-10.96, p < 0.001). Being fully vaccinated represented a significant protective factor (OR 0.12, 95% CI 0.04-0.35, p < 0.001).

CONCLUSION

Older classes of age and a complete vaccination, in time with the recommended schedule, are both protective factors for hospitalisation in severe pertussis disease. The widespread vaccination delay frequently observed in preterm children may be the cause for their higher rate of hospitalisation.

Seroprevalence Study of Pertussis in Adults at Childbearing Age and Young Infants Reveals the Necessity of Booster Immunizations in Adults in China

In China, the vaccination strategy against pertussis is started from 3 months of age, with no booster dose used after the booster given at two years. Despite a high vaccination coverage, pertussis has been increasingly reported since the last decade. This study evaluates the prevalence of serum anti-pertussis toxin (PT) IgG antibodies in adults at childbearing age and infants before the age of primary immunization in Beijing, China. A total of 1175 serum samples randomly selected from individuals who attended an annual health examination at the Sixth Medical Center of the PLA General Hospital, Beijing, in 2019, was included. The geometric mean concentration (GMC) and median concentration of anti-PT IgG antibodies among adults aged 20–39 years were 3.81 IU/mL and 3.24 IU/mL, and the corresponding concentrations were 1.72 IU/mL and 1.43 IU/mL among infants under 3 months of age. The seroprevalence of PT IgG antibodies ≥ 40 IU/mL in adults and infants was 2.0% (15/735) and 1.1% (5/440). In total, 65.99% (485/735) of adults and 83.41% (367/440) of infants had non-detectable pertussis-specific antibodies (<5 IU/mL). Our results showed that the majority of adults at a reproductive age and young infants are vulnerable to pertussis, suggesting that booster vaccinations in adults should be considered in this country.

Descriptive Observational Study of Tdap Vaccination Adhesion in Pregnant Women in the Florentine Area (Tuscany, Italy) in 2019 and 2020

Background: Tdap (Tetanus-Diphtheria-acellular Pertussis) vaccination is nowadays a worldwide-recommended practice to immunize pregnant women. The vaccine administration at the third trimester of pregnancy (as recommended by the WHO) would ensure antibody protection to both the mother and the newborn and has contributed to the significant drop of pertussis cases in infants. The aim of this observational study was to describe for the first time the socio-demographic characteristics and determinants of Tdap vaccination adhesion of pregnant women in the Florentine area. Methods: Information about parents’ vaccination status, their citizenship, employment type and mothers’ previous pregnancies and/or abortions were collected at the time of birth through the assistance birth certificates (CedAP) both for the years 2019 and 2020. This archive and the regional SISPC (Collective Prevention Healthcare Information System) linked using an anonymous unique personal identifier to retrieve the mother’s vaccination status. Results: We found an overall Tdap vaccination adhesion of 43% in 2019 and 47.3% in 2020. Several socio-demographic parameters would determine an increased vaccination adhesion, including parents’ geographical origin, mothers’ age and educational background, as well as the number of previous deliveries, abortions or voluntary termination of pregnancy. Conclusions: Since not much data are available on this topic in Italy, this study may constitute the baseline information for Tdap vaccination adhesion in pregnant women in the Florentine area (Italy). Thus, future successful vaccination strategies may be designed accordingly.

Experience and attitudes on vaccinations recommended during pregnancy: survey on an Italian sample of women and consultant gynecologists

Active immunization in pregnancy is recommended for the influenza and the tetanus, diphtheria, and acellular pertussis (Tdap) vaccines. Evidence indicates vaccine effectiveness in preventing influenza-related hospitalizations and pertussis in early infancy. We investigate vaccine uptake in pregnant and non-pregnant women through a sample of young women and consultant gynecologists, along with the potential predisposing and/or enabling factors affecting attitudes to vaccination (knowledge, beliefs, barriers). A cross-sectional study was conducted between June and September 2019, with a sample of 251 women and 14 consultant gynecologists at the Local Health Authority (ASL01) of the Abruzzo Region (Italy), using an anonymous, self-report questionnaire survey. Among the participants, 5.6% of women had received influenza vaccination, 16.4% had received Tdap during pregnancy and only 1.2% had received both vaccines. The assessment of the psychometric attitudinal variables has suggested a more positive willingness to receive Tdap than influenza vaccine among women, as the former is considered more important for the maternal and neonatal health. Health care workers have reported vaccine safety concerns, lack of information, and misconceptions about the need for vaccination as barriers to immunization in pregnant women. The results of this study will contribute to defining the goals and strategies to increase vaccine uptake under the current recommendations, through promoting effective training programs for all health care workers involved (gynecologists, obstetricians, public health physicians).

Pertussis in early life: underdiagnosed, severe, and risky disease. A seven-year experience in a pediatric tertiary-care hospital

AIM

Pertussis continues to be a common worldwide infection in pediatric and adult populations.We aimed to study epidemiological and clinical characteristics of infants and children admitted for pertussis to a tertiary-care hospital and to investigate the risk factors for pediatric intensive care unit (PICU) admission.

MATERIALS AND METHODS

With a retrospective study, we analyzed all medical reports of patients admitted to Bambino Gesù Children's Hospital in Rome from January 2011 to December 2018 with a diagnosis of pertussis.

RESULTS

We examined 195 patients. The majority of hospitalized children (66.15%) were <3 months of age. No mother had received pertussis containing vaccine during pregnancy. Ten cases required admission in PICU. The age at admission was lower in PICU patients with respect to ward patients (42.8 vs 240 days; p < .0007), length of hospital stay was longer in PICU group (24.7 vs 7.52 days; p < .003). Patients who needed PICU admission had greater white blood cell count at hospital admission compared with those hospitalized in the pediatric ward. One infant died and one had encephalitis.

CONCLUSIONS

Pertussis is a remerging disease. In infants, it is associated with significant morbidity and mortality. In recent years, many countries have implemented different vaccination strategies and public health measures to prevent the increase in pertussis cases. Maternal vaccination has been shown to be highly protective for infants <3 months of age before they can develop their own immunity via vaccination.

Pertussis in Italy: how to protect the "unprotectable"?

Whooping cough continues to be an important public health issue despite high levels of vaccination coverage with acellular pertussis vaccine. Young unimmunized infants represent the most vulnerable group with the highest rates of complications and death. As infant-specific pertussis epidemiologic data, especially among neonates, in Italy were limited, a retrospective observational study of hospitalizations for whooping cough in Italian infants aged <12 months between 2007 and 2018 was conducted to address this knowledge gap. The temporal trend of rates, also stratified for age classes according to the expected age for the administration of vaccine doses, were analyzed by the slope of the regression line. The mean age at the time of admission was 92 d (±64). A clear seasonal pattern in the occurrence of pertussis hospitalizations with a summer peak was observed. Infants younger than 3 months old had the highest hospitalization rates (169 x 100000 infants on average), with a significant rising trend of 9 x 100000 infants on average per year. Limiting the analysis to Bordetella pertussis-related hospitalizations such trend was even more evident. In the other age classes, hospitalization rates were considerably lower and gradually decreased with increasing age. This study demonstrated that pediatric populations, too young to be protected by vaccination, had a greater risk of contracting pertussis. Thus, it is necessary to promote additional immunization strategies besides one booster dose in adolescents, including vaccination during pregnancy.

Pertussis-like syndrome often not associated with Bordetella pertussis: 5-year study in a large children's hospital

Background: Recently, a resurgence of pertussis has been observed worldwide despite broad vaccination coverage. The purpose of this study was to identify the clinical characteristics and the aetiological agent of pertussis-like syndrome (PLS) in Eastern China.Methods: 1168 patients who were diagnosed with a suspected Bordetella pertussis in Shanghai Children's Hospital from 2013 to 2017 were included in the study. Clinical features and aetiologies were analysed. Aetiological analyses in sub-cohorts of age, seasons and years were also investigated.Results: 96.0% (1121) of the patients were less than 12 months old. 59.0% (689) of the patients were male. The Top 5 pathogens were respiratory syncytial virus (RSV; n = 125; 10.7%), Streptococcus pneumonia (SP; n = 109; 9.3%), Haemophilus influenzae type b (HIB; n = 86; 7.4%), Bordetella pertussis (B. pertussis; n = 84; 7.2%), and Mycoplasma pneumonia (MP; n = 80; 6.9%), respectively. The percentage of SP in the age group of 0-3 months was significantly lower than that in other age groups. The percentage of B. pertussis in the age group of 3-6 months was significantly lower than that in the group of 6-12 months. The percentage of MP in 0-3 months' group was significantly lower than that in >12 months group. RSV peaked in winter (n = 52), while HIB peaked in spring (n = 38).Conclusion: PLS occurred most often in infants. RSV, SP, HIB, B. pertussis, and MP were the most prevalent pathogens. Since patients with B. pertussis and other pathogens have similar clinical manifestations, diagnosis of pertussis should be based on both clinical symptoms and laboratory confirmation.

Pertussis immunization in healthcare workers working in pediatric settings: Knowledge, Attitudes and Practices (KAP) of Occupational Physicians. Preliminary results from a web-based survey (2017)

Introduction

The present study aims to characterize knowledge, attitudes and practices in a sample of occupational physicians (OPh) towards pertussis immunization in healthcare workers (HCWs) from pediatric settings.

Material and methods

A total of 148 OPh (45.9% males, mean age of 40.3 ± 13.2 years) compiled a web questionnaire including a knowledge test on Italian recommendations for HCWs, epidemiology and pathology of pertussis infection, being then investigated about risk perceptions and vaccination practices. A General Knowledge Score (GKS) and a Risk Perception Score (RPS) were calculated. Multivariate odds ratios (OR) for predictors of vaccine propensity were calculated through regression analysis.

Results

78 participants regularly recalled pertussis vaccination status and/or performed pertussis vaccination in HCWs (52.7%). Proactive status was correlated with the aim to avoid pertussis infection in HCWs and its diffusion to other adults (p < 0.001, both statements). GKS was satisfying (72.4% ± 14.9), but participants underestimated the clinical issues of pertussis infection (RPS 60.8% ± 9.5) when confronted with influenza (73.9% ± 10.9) and HBV infection (68.1% ± 10.1). GKS and RPS were well correlated (r = 0.244, p = 0.003). Eventually, a better GKS and the aim to avoid pertussis infection in HCWs were predictive of a proactive status for pertussis vaccination (OR 4.186 95%CI 1.809-9.685 and OR 11.459, 95%CI 3.312-39.651, respectively).

Conclusions

Adherence of OPh to HCWs pertussis vaccination was unsatisfying. As knowledge status was predictive for vaccine propensity, information programs for OPh should be more appropriately designed, stressing that HCWs may represent a significant reservoir for pertussis infection in high risk groups (e.g. children/newborns, frail elderly).