|Year : 2020 | Volume
| Issue : 1 | Page : 15-19
Study on the pattern of adverse events following immunization in children aged ≤6 years: A single-center experience
Manohar Badur1, Subramanyam Pujari1, Mrudula Yenepalli1, Latheef Kasala2, Rishika Jayachandra Chintham1
1 Department of Paediatrics, Sri Venkateswara Medical College, Tirupati, Andhra Pradesh, India
2 Department of Clinical Research, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Submission||17-Jul-2020|
|Date of Acceptance||15-Sep-2020|
|Date of Web Publication||06-Nov-2020|
Dr. Manohar Badur
Department of Paediatrics, S. V. Medical College, SVRR General Hospital, Tirupati - 517 507, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Objectives: This study was conducted to observe the incidence of adverse events following immunization (AEFI) in children ≤6 years of age. Material and Methods: An observational study was conducted in the department of pediatrics of our hospital from November 2018 to November 2019. A total of 20,414 children who attended the well-baby clinic for immunization over a period of one year were enrolled and observed for adverse events. Parents of the children were telephonically contacted for the observation of any type of adverse reaction that has followed by the administration of the vaccine. Results: Among 20,414 children, 8246 AEFI were reported during the study period. Majority of the AEFI were reported in the age group <1 week, followed by 6 weeks. Female children (56.7%) had reported more AEFI compared to male children (43.3%) with a ratio of 1.3:1 (F:M). The most common AEFI reported was fever (n = 4195 cases), followed by swelling (n = 2933 cases). Penta + IPV + OPV + Rota (38.2%) was majorly responsible for AEFI, followed by BCG + Hep-B + OPV (35.5%). Most of the AEFI (93.3%) were reported within 1 day of vaccine administration (n = 7691 cases). Conclusion: Our findings revealed that most of the adverse events were observed on day-1 after vaccine administration. Thus, after identifying the vaccines responsible for adverse events and the characteristics of the events, we may continue to consider vaccines as safe biological products. We also recommend that all AEFI should be documented and reported to the Central Drug Standard Control Organization (CDSCO) in real-time regarding vaccine use and awareness of vaccine safety.
Keywords: Adverse events, children, immunization
|How to cite this article:|
Badur M, Pujari S, Yenepalli M, Kasala L, Chintham RJ. Study on the pattern of adverse events following immunization in children aged ≤6 years: A single-center experience. J Pediatr Assoc India 2020;9:15-9
|How to cite this URL:|
Badur M, Pujari S, Yenepalli M, Kasala L, Chintham RJ. Study on the pattern of adverse events following immunization in children aged ≤6 years: A single-center experience. J Pediatr Assoc India [serial online] 2020 [cited 2020 Nov 27];9:15-9. Available from: http://www.indjpai.com/text.asp?2020/9/1/15/300103
| Introduction|| |
The universal immunization programme (UIP) of India is one among the largest immunization programs in the world that targets about 27 million infants and 30 million pregnant women. Like any other pharmaceutical agent, vaccines also carry the risk of adverse events. However, expectations with regard to vaccine safety are high, as they are administered to healthy individuals. Additional booster doses further increase the risk of adverse events. Paradoxically, an effective immunization program will result in decrease in incidence rates of the target diseases, but may result in higher incidence of adverse events.
There is no such thing as a “perfect” vaccine which protects everyone who receives it and is entirely safe for everyone. Effective vaccines (i.e., vaccines inducing protective immunity) may produce some undesirable side effects which are mostly mild and clear up quickly. The majority of events thought to be related to the administration of a vaccine are actually not due to the vaccine itself; many are simply coincidental events, others (particularly in developing countries) are due to human, or program error.
An active search system for adverse events to vaccines is a better method for detecting and quantifying mild adverse events that are usually missed by passive surveillance. However, situations such as underreporting or difficulty in finding casual association between the appearance of the adverse events and the administration of the vaccine tend to hamper pharmacovigilance.
Immunization is one of the most effective health-care practices to prevent serious infectious diseases. Vaccines, unlike medications, are given to healthy individuals for the prevention of a disease. Hence, the expectation on vaccines is very high and vaccine safety is very important. This places the current study in a supreme place by evaluating the adverse events following immunization (AEFI).
| Material and Methods|| |
This was an observational study conducted in the department of pediatrics of our hospital from November 2018 to November 2019. This study was approved by the Institutional Ethics Committee of our medical college. The sample size included all the infants who attended the well-baby clinic during the study period. All the children aged ≤6 years and received immunization were included in the study. Those who did not give consent were excluded.
Study procedures and data collection
All the children received Bacillus Calmette–Guerin vaccine (BCG), oral polio vaccine (OPV), pentavalent, rotavirus vaccine, injectable polio vaccine (IPV), Diphtheria–Tetanus–Pertussis (DPT), hepatitis B, measles vaccines, and Japanese encephalitis vaccine as per the National Immunization Schedule.
To maintain uniformity and identity, pentavalent was injected in the left thigh, hepatitis B vaccine in the right thigh, measles vaccine in the right arm, and BCG vaccine in the left arm. The study protocol was explained in detail to the parents of children. All the parents willing to participate in the study were asked to fill an informed consent form. A Case Record Form was designed to obtain basic information such as demographic data and vaccine details including batch number, date of manufactured, expiry date, manufacturing company, etc.
A telephonic follow-up of parents or guardians was conducted on 2nd day, 7th day, and on 30th day after the vaccine administration date.
The parents of children were inquired about the observation of any type of reaction that has followed by the administration of the vaccine. The parents/guardians of children were also given the telephone number of the investigator so that they can contact in case of any problem followed by vaccine administration.
All the statistical analyses were performed on Microsoft Excel spreadsheets and Statistical Package for the Social Sciences software (SPSS) for Microsoft Windows, version 20.0 (IBM Corp., Somers, NY, USA). Data were collected on predefined proforma and transformed into MS Excel spreadsheets. All the entries were double checked to minimize the data entry errors. Descriptive statistics included frequencies and percentages for categorical variables were calculated.
| Results|| |
A total of 20,414 children were attended to well-baby clinic for immunization over a period of 1 year. The distribution of children age group attended for immunization is summarized in [Table 1]. Among the 20,414 children, 43.1% (n = 8798) were male children and 56.9% (n = 11616) were female children.
Distribution of adverse events following immunizations
A total of 8246 (40.4%) AEFI were documented during the study period from 20,414 children. The distribution of AEFI's based on age and gender of the children is summarized in [Figure 1]. Majority of the AEFI were reported in the age group < 1 week, followed by 6 weeks. Female children (56.7%) had reported more AEFI compared to male children (43.3%) with a ratio of 1.3:1 (F:M).
|Figure 1: Distribution of AEFI based on age and gender. AEFI: Adverse event following immunization|
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Distribution of suspected vaccines for different adverse events following immunization
[Table 2] shows the frequency distributions of AEFI and suspected vaccines. The most common AEFI reported was fever in 4195 cases in that most cases due to Penta + IPV + OPV + Rota vaccines with cases of 1826 (43.5%). Swelling was the second most common AEFI which was reported in 2933 cases, of these, majority were due to BCG + Hep-B + OPV with cases of 1496 (51%) [Figure 2].
|Table 2: Frequency distribution of suspected vaccines for different adverse event following immunization|
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|Figure 2: Distribution of different AEFI. AEFI: Adverse event following immunization|
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Overall, Penta + IPV + OPV + Rota (38.2%) was majorly responsible for AEFI, followed by BCG + Hep-B + OPV (35.5%) [Figure 3].
|Figure 3: Distribution of suspected vaccine for the AEFI. AEFI: Adverse event following immunization; BCG: Bacillus Calmette–Guerin vaccine; Hep-B: Hepatitis B; OPV: Oral polio vaccine; IPV: Injectable polio vaccine; MR: Measles and rubella; JE: Japanese encephalitis; DPT: Diphtheria–Tetanus–Pertussis|
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Day of presentation of adverse events following immunization
[Table 3] shows the day of onset of AEFI after administration of vaccine; most of the AEFI (93.3%) were reported within 1 day of vaccine administration (n = 7691 cases).
| Discussion|| |
Vaccine's post licensure surveillance is an essential part of an immunization program which continuously monitors the safety of routinely used vaccines. The present study was performed to assess the pattern of adverse events following BCG, OPV, IPV, pentavalent, hepatitis-B, MR, Japanese encephalitis, rotavirus, and DPT Booster vaccines administration.
In this study, during the 1-year period, we have studied 20,414 children belong to various age groups. Total vaccine doses administered were 60,548 (oral – 17,649 and injectables – 42,899). Out of them, 8246 AEFI were documented during the study period. Majority of the AEFI were reported in the age group < 1 week, followed by 6 weeks. Female children (56.7%) had reported more AEFI compared to male children (43.3%) with a ratio of 1.3:1 (F: M). The most common AEFI reported was fever (n = 4195 cases), followed by swelling (n = 2933). Overall, Penta + IPV + OPV + Rota (38.2%) was majorly responsible for AEFI, followed by BCG + Hep-B + OPV (35.5%). Most of the AEFI (93.3%) were reported within 1 day of vaccine administration (n = 7691 cases).
Monitoring AEFI from the day of vaccination is crucial for the attainment of results in real time. It is important not to miss any day post vaccination, especially during the first 7 days, because most of the AEFIs occurred within this period.,
In our study, the incidence rate of AEFI was 13.6/10,000 doses. It is similar to the study on passive surveillance data for AEFI in China for a 3-year period, which had an incidence rate of 9.2/100,000 doses. In another study conducted in Singapore, the incidence of AEFI for a 2-year period was 4.4%. This rate in Cuba was 57.8/100,000. The overall dose-based reporting rate for the 27 frequently reported vaccine types in the United States was 11.4/100,000 net doses distributed.
The majority of AEFI were from the age group of <1 year in the present study. This could be because most of the vaccine doses were administered at this age according to the National Immunization Programme. In that, most of them were reported within one week as 68% of vaccine doses were given, and the reported AEFI were 2927 (35.4%). As our study was conducted at an immunization clinic at a maternity hospital, all the babies who were delivered are getting vaccinated, and after discharge, these babies were vaccinated at their respective primary health-care centers by health-care workers.
Our findings also showed that 35.5% of the AEFI were related to BCG + OPV + Hep-B vaccines, of which 51.1% were swelling and 35.8% were fever. The results of our study are in consistent with other published studies which had reported that 41% of AEFI were related to the BCG vaccine.,
In the present study, the most common AEFI was fever (50.9%), followed by swelling at the injection site (35.6%) in both males and females. These results are in concordance with the studies done by Joshi et al. in India and Carrasco-Garrido et al. in Spain. Zhou et al. in the US and Joshi et al. in India also found fever as the most common adverse event. The study by Hu et al. in China and Zhang et al. also stated that the most frequently reported AEFI was fever, followed by injection site reaction and allergic reaction.
The study was conducted at single center, duration was short, and follow-up was done by telephonic calls. The outcome of this study may not be applicable to population vaccinated at primary health centers, private hospitals, and in camp by nongovernment organizations as this study was conducted at a tertiary care hospital. Multicentric studies are required to generalize these study findings.
| Conclusion|| |
Our findings revealed that most of the adverse events were observed on day-1 after vaccine administration. Thus, after identifying the vaccines responsible for adverse events and the characteristics of the events, we may continue to consider vaccines as safe biological products. We also recommend that all AEFI should be documented and reported to the Central Drug Standard Control Organization (CDSCO) in real-time regarding vaccine use and awareness of vaccine safety.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]