Adverse events following immunization with pentavalent vaccine: experiences of newly introduced vaccine in Iran

Vaccine Safety: Assessing the Prevalence and Severity of Adverse Events Following COVID-19 Vaccination amongst Healthcare Workers in Tertiary Health Facilities in Nigeria

BACKGROUND

Vaccines, including COVID-19 vaccines, are known to be cost-effective interventions for disease prevention and control. However, adverse events following immunisation (AEFI) may challenge the acceptance of these vaccines. This study assessed the prevalence and severity of COVID-19-related AEFI amongst healthcare workers at tertiary health facilities in Nigeria.

MATERIALS AND METHODS

This descriptive, cross-sectional study was conducted among healthcare workers who had received the COVID-19 vaccine. A multi-stage sampling technique was used to select participants from six Tertiary Health Facilities in Nigeria. Ethical approval (NHREC/01/01/2007-19/07/2021) was obtained from NHREC. Data were analysed using IBM® SPSS version 25 and categorical variables were presented in tables/charts using frequencies and proportions.

RESULTS

A total of 2130 respondents participated in the study, with a mean age of 37.4 ± 9.1 years. Most of the respondents, 1674 (78.6%), had two doses of the vaccine, and the overall prevalence of AEFI was 813 (38.2%). Common among the AEFI reported following the administration of the first dose of the vaccine were fever 649 (30.5%) and pain at the injection site 644 (30.2%), while it was pain at the injection site 216 (10.1%) and fever 173 (8.1%) for second dose. The higher proportions of AEFI were mostly mild to moderate.

CONCLUSION

The study observed a relatively low prevalence of AEFI, with the commonly reported ones being fever and injection site pain. It is crucial that countries continuously collect the data on AEFI and establish causality as a way to improve quality and guarantee vaccine safety.

Factors associated with pentavalent vaccine coverage among 12-23-month-old children in Afghanistan: A cross-sectional study

INTRODUCTION

This study aimed to identify the factors associated with the coverage of the third dose of pentavalent vaccine (Penta3) among children aged 12-23 months in Afghanistan.

METHODS

The data of 3,040 children aged 12-23 months were taken from the Afghanistan Health Survey 2018, including characteristics of the children and their households, household heads, and mothers/primary care givers. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were estimated using a logistic model. Multivariable stepwise logistic regression analysis with forward-selection (Model 1) and backward-selection (Model 2) was performed using variables that showed significant differences by bivariate analysis.

RESULTS

The coverage of Penta3 among 12-23-month-old children was 82.3%. Factors associated with Penta3 coverage in the two models of multivariable analysis were 18-23 months old compared to 12-17 months old; having no diarrhea in the last two weeks compared to having diarrhea; no bipedal edema compared to having edema; taking vitamin A supplement; 1-2 children under five years in a household compared to three or more; distance from residence to the nearest health facility ≤2 hours on foot; having a radio; having a TV; educated heads of households; non-smoking of heads of households; and literacy of mothers/primary caregivers.

CONCLUSIONS

Penta3 coverage among 12-23-month-old children improved but was still lower than the target. Primary education should be provided to all children throughout the country. TV and radio are useful tools for providing health information. Mobile outreach programs and the establishment of new health facilities should be promoted to improve access to health service for all people in Afghanistan.

Change in Prevalence of Meningitis among Children with Febrile Seizure after the Pentavalent Vaccination

Introduction

One of the most significant current discussions in pediatrics is whether lumbar puncture (LP) should be performed in children with febrile seizure (FS) as in the past.

Objectives

We compared the prevalence of meningitis among FS children before and after the pentavalent vaccine to determine the importance of the LP in these children.

Methods

We performed a retrospective cross-sectional study on the prevalence and etiology of bacterial meningitis (BM) in 1314 children with FS before and after pentavalent vaccination.

Results

We found that complex FS was more prevalent in patients aged under 12 months compared to other patients. The peak incidence of aseptic meningitis and BM was in the age group of 12- to 18- and 18- to 36-month-old, respectively (P value <0.001 and <0.05, respectively). Children with complex FS had a significantly higher rate of BM and a lower rate of seizure recurrence than those with simple FS (P value <0.05). There was a significant relationship between getting the pentavalent vaccine and reducing the prevalence of BM and Hib-induced BM, but no SP-induced BM (P value <0.05 and 0.05 and 0.104, respectively).

Conclusion

This study offers some insights into the effectiveness of the pentavalent vaccine. In addition, the low prevalence of BM in vaccinated FS cases does not support strong recommendations for LP in FS children.

Adverse events following pediatric immunization in an Indian city

Purpose

Adverse effects are noticeable immediately after vaccination, especially when vaccinated to healthy people at the time of vaccination. The vaccine may cause adverse events which are very rare but adverse event following immunization surveillance becomes correspondingly more important in a less studied population like India. Hence, there is a need for carrying out a study pertaining to vaccine safety in the pediatric population of age 0-12 years and assessing the events occurring post-vaccination.

Materials and Methods

A prospective observational study was conducted in three primary healthcare centers and two tertiary care hospitals for 6 months from April 2016 to September 2016 with a total of 826 children enrolled. Detected adverse events for suspected vaccines were analyzed for causality by the World Health Organization causality assessment instrument. Sex-specific differences in incidences of adverse events were assessed.

Results

The cumulative adverse events were found highest in pentavalent vaccines (510 incidences, 62.04%) followed by the bacillus Calmette-Guérin vaccine (189 incidences, 22.99%). The study didn't reveal any significant association in incidences of adverse events following immunization and sex of the children.

Conclusion

Vaccine safety surveillance studies are need of the hour in developing countries to maintain public trust in vaccines, the ultimate objective being to have vaccines with the most favorable benefit-risk profile. The present study discussed the various adverse events following immunization and suggested the absence of any sex-specific difference in incidences of adverse events in children.

Effect of Haemophilus influenzae Type b Vaccination on Nasopharyngeal Carriage Rate in Children, Tehran, 2019

Background

Haemophilus influenzae (H. influenzae) strains, which commonly reside as commensals within the human pharynx and can remain as an asymptomatic carrier, but become invasive leading to pneumonia, septic arthritis, or meningitis. The Pentavac (pentavalent vaccine, manufactured by India, SII (DTwP-HepB-Hib)) was introduced to the Iranian National Immunization Plan in November 2014. The aim of this study is to investigate H. influenzae type b (Hib) carrier rate among children under 6 years old in Tehran.

Methods

This cross-sectional study was performed on 902 children including vaccinated/unvaccinated in the age of 6 months to 6 years, in Tehran. Sampling was performed from July 2019 to September 2019. Nasopharyngeal samples were taken from children by sterile swab. The PCR method was used to extract DNA. Then, all H. influenzae isolates were initially confirmed by molecular tests. BexA was used to distinguish typeable H. influenzae strains from nontypeable Haemophilus influenzae (NTHi).

Results

A total of 902 children were enrolled in the study: 452 were female (51%). H. influenzae carriage rate was 267 (29%), of that 150 samples (16.6%) were typeable. The nasopharyngeal Hib carrier rate in the children was 2.6% (24/902). 262 cases did not receive Hib vaccine. Analysis in nonnursery's children aged 4 to 6 (unvaccinated) years showed that the lower educational level of father, mother, and family number correlated with increased odds of colonization of children with Hib.

Conclusion

Our findings showed a significant decrease (60%) in the overall Hib nasopharyngeal carriage in healthy children under six years after 5 years after the start of Hib vaccination.

Immunogenicity and Complications of the Pentavalent Vaccine in Iranian Children

Objective: Vaccination is one of the most convenient and safe preventive care measures available for children. The Pentavalent vaccine which protects against five major infections including diphtheria, tetanus, pertussis, hepatitis B(HepB) and Haemophilus influenzae type b(Hib) was added to the Iranian national immunization program in November 2014. This study aimed to determine the Pentavalent vaccine adverse events and immunogenicity in an Iranian children population in Sari, northern Iran. Method: In this descriptive-analytical study, children who were vaccinated with three doses of the Pentavalent vaccine were studied. Two venous blood samples were obtained before the first dose and 4 weeks following the last booster dose. Possible local and systemic complications of the vaccine were recorded until 7 days following vaccination. Antibody titers were measured by quantitative ELISA kits and geometric mean titer(GMT) was calculated for each vaccine component before and after 3 doses of vaccine. Statistical analysis was performed by SPSS 20.0 software and Chi-square and Fisher's exact tests were used for analysis. Results: Immunogenicity of the Pentavalent vaccine for tetanus was 100%(GMT:2.52 Eu/mL, 95%CI: 2.22-2.88), Hib 98.7%(GMT:2.44 Eu/mL, 95%CI: 2.06-2.89), HepB 98.7%(GMT:153.54 Eu/mL, 95%CI: 133.73-176.29), diphtheria 93.1%(GMT:0.43 Eu/mL, 95%CI:0.37-0.51) and pertussis were 63.7% (GMT:19.44 Eu/mL, 95%CI:16.42-23.03). The most common systemic complication after vaccination was fever. Also, one infant cried for more than 3 hours after the second dose. Other serious side effects were not observed. Conclusion: The Pentavalent vaccine used in Iran can cause adequate antibody response against diphtheria, tetanus, pertussis, Hib and hepatitis B in most cases with minimal side effects. The immunogenicity of this vaccine is significantly lower for pertussis. In this study, no severe complication leading to contraindication to subsequent injections was reported. So, the present policy in replacing triple DTP vaccine with Pentavalent vaccine should be continued in Iran.

Estimation of the wastage rate of MMR and pentavalent vaccines in open and closed vials in three western provinces of Iran

Background

Vaccine wastage is one of quality indicators of immunization program and high vaccine wastage will increase overall costs and impede efforts towards a more efficient and sustainable program. We aimed at estimating of the wastage rates of Measles-Mumps-Rubella (MMR) and pentavalent (diphtheria-tetanus-pertussis-hepatitis B -Haemophilus influenza type b) vaccines in different vaccine vial sizes.

Study design

Multicentre descriptive study using existing data.

Methods

This study was in three provinces (Hamadan, Kermanshah and Kordestan) of Iran including 131,135 populations with 2,548 under-1years children. Twenty-seven health facilities were selected randomly from nine districts in three provinces of western part of Iran. Six-months data including vaccination and vaccine stock records collected from April to September 2017. Finally, number of opened vials and number of target population vaccinated were collected and data were analysed to estimate the wastage rates in both unopened and opened vials of both antigens.

Results

The wastage rate for combined MMR 2-dose and 5-dose opened vials for three provinces was 29%(Hamadan 18%, Kermanshah 14% and Kordestan 52%). The wastage rate for combined pentavalent single-dose and 10-dose vials for three provinces was 17% (in Kordestan33%, 11% Kermanshah 11% and Hamedan 3%). The total average of pentavalent single-dose and 10-dose vials wastage rate was 5% and varied 13% for urban and 3% for rural areas. The average of discarded unopened vials wastage rate in all facilities for MMR was 3.9% (3.2% for MMR 2-dose vial and 10.2% for MMR 5-dose vial). This rate was 1.7% for pentavalent total (1.9% for single dose vial and 0.4% for 10 dose vial).

Conclusion

The vaccine wastage rates in Iran are in line with other countries and lower than the suggested rate based on WHO policies for multi-dose vials. The wastage rates were different for in provinces, districts and health facilities. The MMR total wastage rate in rural is higher than those in urban areas. However, the pentavalent total wastage rate was higher in urban area.

The Comparison of the Adverse Events of Pentavalent Vaccine and DPT Vaccine in 2-6 Months Infants in Iran: A National Study

Background

Vaccination is the most remarkable intervention in public health and is an effective strategy in controlling infectious diseases among infants.

Objectives

The aim of this study was to compare the adverse events of Pentavalent vaccine and DPT vaccine in two- to six-month-old infants in Iran.

Methods

This is an analytical cross-sectional study in which healthy infants aged two to six months, having received DPT vaccine in 2013 and Pentavalent vaccine in 2015, were studied for any experienced adverse events related to these vaccines. Percentage, mean, standard deviation and chi-square tests were used to describe and analyze the data (p < 0.05).

Findings

The results showed that 10,464 and 17,561 adverse events, which were associated with DPT vaccine and Pentavalent vaccine respectively, were recorded in the infants who received these vaccines throughout Iran. Mazandaran, Qazvin and Golestan provinces reported the highest number of adverse events, respectively (15.74%, 11.25%, and 9.12%). Moreover, Pentavalent vaccine seemed to have more recorded adverse events compared to DPT, high fever had the highest record rate for DPT vaccine (47.4%) and mild localized complications was the highest for Pentavalent vaccines (31.68%). There was a significant relationship between the kind of vaccine and the type of reaction, adverse event categorization and the country that produced the vaccine (p < 0.05).

Conclusion

Severe localized adverse events including high fever, vomiting, diarrhea and restlessness seemed to be less in Pentavalent vaccine compared to DPT vaccine. Therefore, substituting Pentavalent vaccine for DPT vaccine in infants seems to reduce the adverse events among them.