Rates Of Adverse Events Following Immunization Research Articles

Post-Marketing Surveillance of Adverse Events Following Immunization with Haemophilus Influenzae Type b Conjugate Vaccine - China, 2010-2021.

The Haemophilus influenzae type b (Hib) conjugate vaccine is widely administered in China. We extracted data on Hib vaccine doses administered and adverse events following immunization (AEFI) reported between 2010 and 2021 from the Chinese National Immunization Information System (CNIIS). A descriptive analysis was conducted to examine the characteristics and incidence rates of AEFI with the Hib vaccine. In China, between 2010 and 2021, a total of 52,910 AEFIs with the Hib vaccine were reported, resulting in an overall AEFI reporting rate of 38.10 per 100,000 doses. Common (typically minor) and rare (potentially serious) vaccine reactions occurred at rates of 34.71 and 2.78 per 100,000 doses, respectively. Among the common vaccine reactions, the incidences of fever (axillary temperature ≥38.6 ℃), injection site redness and swelling (>2.5 cm in diameter), and injection site induration (>2.5 cm in diameter) were 11.93, 9.69, and 3.38 per 100,000 doses, respectively. Rare vaccine reactions included anaphylactic rash, angioedema, and febrile convulsion with reported incidences of 2.42, 0.10, and 0.05 per 100,000 doses, respectively. The incidence of serious rare vaccine reactions was 0.16 per 100,000 doses. The reported incidence of AEFI with the Hib vaccine was low, with the occurrence of serious rare adverse reactions also being markedly low throughout the period 2010-2021 in China.

Adverse Events of COVID-19 Vaccines in the United States: Temporal and Spatial Analysis.

The COVID-19 pandemic, caused by SARS-CoV-2, has had a profound impact worldwide, leading to widespread morbidity and mortality. Vaccination against COVID-19 is a critical tool in controlling the spread of the virus and reducing the severity of the disease. However, the rapid development and deployment of COVID-19 vaccines have raised concerns about potential adverse events following immunization (AEFIs). Understanding the temporal and spatial patterns of these AEFIs is crucial for an effective public health response and vaccine safety monitoring. This study aimed to analyze the temporal and spatial characteristics of AEFIs associated with COVID-19 vaccines in the United States reported to the Vaccine Adverse Event Reporting System (VAERS), thereby providing insights into the patterns and distributions of the AEFIs, the safety profile of COVID-19 vaccines, and potential risk factors associated with the AEFIs. We conducted a retrospective analysis of administration data from the Centers for Disease Control and Prevention (n=663,822,575) and reports from the surveillance system VAERS (n=900,522) between 2020 and 2022. To gain a broader understanding of postvaccination AEFIs reported, we categorized them into system organ classes (SOCs) according to the Medical Dictionary for Regulatory Activities. Additionally, we performed temporal analysis to examine the trends of AEFIs in all VAERS reports, those related to Pfizer-BioNTech and Moderna, and the top 10 AEFI trends in serious reports. We also compared the similarity of symptoms across various regions within the United States. Our findings revealed that the most frequently reported symptoms following COVID-19 vaccination were headache (n=141,186, 15.68%), pyrexia (n=122,120, 13.56%), and fatigue (n=121,910, 13.54%). The most common symptom combination was chills and pyrexia (n=56,954, 6.32%). Initially, general disorders and administration site conditions (SOC 22) were the most prevalent class reported. Moderna exhibited a higher reporting rate of AEFIs compared to Pfizer-BioNTech. Over time, we observed a decreasing reporting rate of AEFIs associated with COVID-19 vaccines. In addition, the overall rates of AEFIs between the Pfizer-BioNTech and Moderna vaccines were comparable. In terms of spatial analysis, the middle and north regions of the United States displayed a higher reporting rate of AEFIs associated with COVID-19 vaccines, while the southeast and south-central regions showed notable similarity in symptoms reported. This study provides valuable insights into the temporal and spatial patterns of AEFIs associated with COVID-19 vaccines in the United States. The findings underscore the critical need for increasing vaccination coverage, as well as ongoing surveillance and monitoring of AEFIs. Implementing targeted monitoring programs can facilitate the effective and efficient management of AEFIs, enhancing public confidence in future COVID-19 vaccine campaigns.

Adverse events following immunization of co- and separate administration of DTaP-IPV/Hib vaccines: A real-world comparative study

ABSTRACT To fully understand the safety of DTaP-IPV/Hib vaccination, we evaluated the differences between DTaP-IPV/Hib co-administration and separate administration of the DTaP, IPV and Hib vaccines (DTaP+IPV+Hib) based on adverse events following immunization (AEFI). All AEFI reported in Hebei Province, China, between 2020 and 2022 were included in this study. The risk difference (RD%), relative risk (RR), and Chi-square value were used to compare the differences in reported rates of AEFI between the DTaP-IPV/Hib and DTaP+IPV+Hib groups. From 2020 to 2022, 130 AEFI cases were reported in Hebei Province after DTaP-IPV/Hib vaccination, corresponding to an AEFI reported rate of 66.9/million doses, which was significantly lower than that for DTaP+IPV+Hib (9836 AEFI with a reported rate of 637.8/million doses). The overall reported rate of non-severe AEFI for DTaP+IPV+Hib vaccines was 9.5 times that of DTaP-IPV/Hib vaccination [95% confidence interval (CI): 8.0, 11.3]. Meanwhile, the reported rate of AEFI among infants aged 0–1 y was 9.8 times higher for DTaP+IPV+Hib than for DTaP-IPV/Hib (95% CI: 8.2, 11.7). DTaP+IPV+Hib vaccination also resulted in higher risks of high fever, localized redness and swelling, localized induration, and allergic rash compared with DTaP-IPV/Hib vaccination. The risk of AEFI, which were mostly mild reaction, was higher after vaccination with DTaP+IPV+Hib than after DTaP-IPV/Hib vaccination.

Surveillance for adverse events following immunization with DTaP-containing combination vaccines in Linping, China, 2019-2022.

The DTaP-Hib and DTaP-IPV/Hib combination vaccine can be used as a substitute for the diphtheria, tetanus, and acellular pertussis combined vaccine (DTaP). We aimed to evaluate the safety of multi-component vaccines containing DTaP by analyzing the reporting rates and characteristics of adverse events following immunization (AEFIs) in Linping District during the years 2019 to 2022. We obtained data of AEFI and vaccination from the National AEFI Surveillance System of China and Zhejiang Municipal Immunization Information Management System, respectively, during 2019-2022 for a descriptive, epidemiological analysis. The total number of AEFI reported following vaccinations with DTaP-containing combination vaccines was 802 in Linping District from 2019 to 2022. The overall reporting rates of AEFIs following DTaP, DTaP-Hib, and DTaP-IPV/Hib vaccinations were 445.72 (537 cases), 536.29 (45 cases), and 306.13 (220 cases) per 100,000 doses in Linping District from 2019 to 2022, respectively. Only one case of a serious AEFI following DTaP vaccination, with a reporting rate of 0.83 per 100,000 doses. The composition ratio of vaccine product-related reactions for DTaP, DTaP-Hib, and DTaP-IPV/Hib were 99.81, 97.78, and 100.00%, respectively. The composition ratio of coincidental events for DTaP and DTaP-Hib were 0.19 and 2.22%, respectively. The reporting rates of total AEFIs for DTaP-IPV/Hib were lower than for DTaP. The reporting rate of local induration for DTaP-Hib was lower than for DTaP, and the reporting rates of local redness & swelling and local induration for DTaP-IPV/Hib were both lower than for DTaP. DTaP-IPV/Hib had a higher proportion of AEFIs in first quarter compared to DTaP. The reporting rate after the second dose of DTaP-Hib was higher than that of DTaP, and the reporting rates of AEFIs after the first dose and third dose of DTaP-IPV/Hib were lower than DTaP. The reported AEFIs to multi-component vaccines containing DTaP components during 2019-2022 in Linping District were mainly mild vaccine reactions. DTaP-containing combination vaccines demonstrated a good safety profile.

Surveillance on Adverse Events Following COVISHIELD (ChAdOx1 nCoV-19) vaccination in Goa, India: An Observational Study.

COVISHIELD, ChAdOx1 nCoV- 19 Corona Virus Vaccine was granted emergency use authorization (EUA) as the first vaccine in India in January 2021. Knowing what to anticipate after vaccination will reduce vaccine hesitancy in the public. This study aimed to identify and measure the adverse events following COVID-19 vaccination. A cross-sectional observational study was conducted at Goa Medical College, starting on February 21 till May 23, 2021. A total of 418 people were enrolled. We collected the data using the Microsoft Form and analyzed using Microsoft Excel and R-program. Of the 418 vaccine recipients, the incidence rate of AEFI (Adverse Events Following Immunization) was 54.31%. Fever, fatigue, and headache were the most commonly reported systemic AEFIs. Among these, 54.7% of AEFI were mild, 42.38% were of the moderate category, and only 2.96% were of grade 3 severity. None of the AEFIs were severe enough for hospitalization. Most of them developed symptoms within 24 hours of the first dose. Complete recovery from AEFIs took a median time of 24 hours. Most of our study findings were consistent with the phase 1, 2/3 trials findings of Oxford-AstraZeneca's ChAdOx1 vaccine. The AEFI symptoms were considered immune reactions to the vaccine. The AEFIs were more common among younger individuals and females. The chance of missing a serious adverse event like a thromboembolic phenomenon cannot be ruled out. We observed low AEFI rates with COVISHIELD in the Indian population compared to Oxford- AstraZeneca's ChAdOx1 vaccine in the UK-based population, which can be explained by preexisting immunity against adenovirus in the Indian population. However, based on the study findings, we may interpret that the COVISHIELD, Serum Institute of India, carries a good safety profile overall.

Safety profile of inactivated COVID-19 in healthy adults aged ≥ 18 years: A passive surveillance in Indonesia.

Coronavirus Disease 2019 (COVID-19) vaccination in Indonesia has shown effectiveness in reducing the morbidity and mortality of Covid-19. The study aims to evaluate the incidence rate and severity of Adverse Events Following Immunization (AEFI) of inactivated SARS-CoV-2 vaccine during the first quarter of 2021 until the second quarter of 2022 in Indonesia. More than two hundred million Sinovac/CoronaVac were given from January 13th, 2021, until June 30th, 2022. Data for this study were collected manually and electronically from the national vaccine safety website managed by the National Committee (NC) of AEFI Indonesia and the Ministry of Health Indonesia. The total number of injections observed in the study was 264,311,992 doses consisting of 142,449,795 (first dose), 121,613,324 (second dose), and 248,873 (booster dose). Of the injections given, 301 subjects with Serious AEFIs (SAE) and 10.261 subjects with non-serious AEFIs (AE) reported, with a majority of SAE and AEs found in the first dose. Most of the SAEs were classified as coincidental events by the NC AEFI (IR 0.8/1 million doses on first dose injection; 0.31 on second dose injection). ISRR (immunization stress-related response) is in the second rank of SAEs reported (0.59 IR/1 million doses on the first dose; 0.14 on the second dose). The incidence rate of SAEs and AEs, both in the variable of age, sex, and symptoms per 1 million dose injections in Indonesia, was very rare according to WHO guidelines. Most SAEs were classified as coincidences or unrelated to the vaccine. The result showed that the Sinovac/CoronaVac in Indonesia is safe.

Safety profile and SARS-CoV-2 breakthrough infections among HCWs receiving anti-SARS-CoV-2 and influenza vaccines simultaneously: an Italian observational study

In October/December 2021, World Health Organization and other international agencies recommended the offer of the third dose of anti-SARS-CoV-2 vaccine. In this period, the routine offer of seasonal influenza vaccination was also guaranteed and simultaneous administration of the two vaccines was encouraged.This study aims to evaluate the safety profile and to estimate the incidence of SARS-CoV-2 breakthrough infections in subjects receiving the anti-SARS-CoV-2 and influenza vaccines simultaneously.The study population was represented by healthcare workers (HCWs) of Bari Policlinico General Hospital who received the influenza (Flucelvax Tetra®) and/or anti-SARS-CoV-2 vaccination (BNT162b2 mRNA COVID-19 vaccine, Comirnaty®) either in coadministration or separately in October 2021. Reports of adverse events following immunization (AEFIs) were investigated to study the safety of both vaccines in coadministration and in separate-instance administration. Post-vaccination SARS-CoV-2 breakthrough infection was also studied.942 HCWs accepted to join our study. 610/942 received both vaccines simultaneously. 25.26 % subjects (238/942) were only vaccinated against SARS-CoV-2, while the remaining 94 HCWs received the influenza vaccination first and subsequently received the anti-SARS-CoV2 booster dose.717 HCWs reported AEFIs (Reporting Rate 76.1 per 100 subjects). Simultaneous administration of the two vaccines was not related with an increase of the rate of AEFIs compared to the single administration of SARS-CoV-2 vaccine, but the AEFIs’ rate was lower among subjects who received only influenza vaccine.Post-vaccination SARS-CoV-2 infections were notified for 41.5 % of enrolled subjects (391/942). Incidence of breakthrough infection and symptomatic disease was not significantly different between the simultaneous administration group and other subjects.Our data suggests that simultaneous administration of a quadrivalent influenza vaccine and an mRNA anti-SARS-CoV-2 vaccine neither affected the safety of said products nor was associated with a higher risk of SARS-CoV-2 breakthrough infection.

Stimulated Reporting of Adverse Events Following Immunization with COVID-19 Vaccines.

In India, up until December 2021, Covishield and Covaxin vaccines against COVID-19 were being used for mass vaccination programs. In view of the urgency of fighting the ongoing pandemic, many vaccines have been granted emergency use approval while phase 2/3 clinical trials were still underway. Even for vaccines that have completed phase 3 trials, safety data may not be comprehensive. This retrospective observational study was conducted at a designated Regional Training Centre for Pharmacovigilance cum Adverse Drug Reaction Monitoring Centre (AMC) under the Pharmacovigilance Programme of India. The data sources were stimulated spontaneous reports of Adverse Events Following Immunization (AEFI) due to the COVID-19 vaccines from 10 January to 31 December 2021. A total of 51,010 COVID vaccine doses were administered during the study period. There were 330 AEFI reported (AEFI rate: 0.65%). Six AEFI were serious events among which three were Adverse Events of Special Interest. The majority of the AEFI were systemic, reported after the first dose, and with an onset between 1 and 24 h after vaccination. On comparing Covishield and Covaxin, there were no statistically significant differences in the AEFI reported with either vaccine in terms of gender, seriousness, lag period, duration, recovery, causality, treatment received for AEFI, presence of co-morbidity, or history of COVID-19 infection. Overall, the rates of AEFI was uncommon, and serious AEFI were rare with both Covishield and Covaxin, with a higher rate after the first dose. Whether immunological tolerance or allayed anxiety was responsible for the lower AEFI risk with the second dose remains to be investigated.

Real-world safety profile of the 9-valent human papillomavirus vaccine: A study in Zhejiang, China from 2019 to 2021

ABSTRACT The safety profile of the 9-valent human papillomavirus vaccine (9vHPV) was evaluated based on the reporting rate of adverse events following immunization (AEFI) obtained from the passive surveillance data in Zhejiang. The 9vHPV AEFI reports in Zhejiang were collected and reviewed from the National Adverse Event Following Immunization Surveillance System (NAEFISS) from 2019 to 2021. Reporting rates of AEFI were analyzed under multiple aspects, including age, city, number of vaccinations, AEFI categories, and diagnosis categories. This study used the reporting odds ratio (ROR) for anomalous signal assessment. The NAEFISS collected 331 AEFI reports after administering 1,064,851 doses of 9vHPV, with a crude AEFI rate of 3.12/10,000 doses. The third dose had the highest reporting rate of minor vaccine-related reaction (n = 80, 3.06 per 10,000), followed by the first dose (n = 134, 2.98 per 10,000), and second dose (n = 76, 2.15 per 10,000). Fever/redness/induration was the most common minor adverse event (281 records, 2.64/10,000 doses). Nine cases of urticaria, ten cases of allergic rash, and ten cases of syncope were recorded. This study found a positive signal association between 9vHPV immunization and adverse events such as syncope, encephalitis, sterile abscess, and urticaria. This study did not identify any new emerging safety concerns. In the future, more research is needed to validate and further explore adverse reactions associated with 9vHPV.

Investigation of Adverse Events Experienced by Healthcare Workers following Immunization with Homologous or Heterologous COVID-19 Booster Vaccinations

A comparative analysis was performed to investigate the potential risk factors of Adverse Events Following Immunization (AEFI) after receiving different booster vaccines. From 18 January 2021 to 21 January 2022, the Health Care Workers (HCWs) of Guizhou Provincial Staff Hospital (Guizhou Province, China) who received a third Booster vaccine, that was either homologous (i.e., (i) a total of three doses of Vero cell vaccine or (ii) three doses of CHO cell vaccine) or (iii) heterologous with two first doses of Vero cell vaccine, being either CHO cell vaccine or adenovirus type-5 (Ad5) vectored COVID-19 vaccine, were asked to complete a self-report questionnaire form to provide information on any AEFI that may have occurred in the first 3 days after vaccination with the booster. The frequency of AEFI corresponding to the three different booster vaccines was compared, and the risk factors for predicting AEFI were determined by multivariate logistic regression analysis. Of the 904 HCWs who completed the survey, 792 met the inclusion criteria. The rates of AEFI were 9.8% (62/635) in the homologous Vero cell booster group, 17.3% (13/75) in the homologous CHO cell booster group, and 20.7% (17/82) in the heterologous mixed vaccines booster group, and the rates were significantly different (c2 = 11.5, p = 0.004) between the three groups of vaccines. Multivariate logistic regression analysis showed that: (1) compared to the homologous Vero cell booster group, the risk of AEFI was about 2.1 times higher (OR = 2.095, 95% CI: 1.056-4.157, p = 0.034) in the CHO cell booster group and 2.5 times higher (OR = 2.476, 95% CI: 1.352-4.533, p = 0.003) in the mixed vaccines group; (2) the odds for women experiencing AEFI were about 2.8 times higher (OR = 2.792, 95% CI: 1.407-5.543, p = 0.003) than men; and (3) compared to the non-frontline HCWs, the risk of AEFI was about 2.6 times higher (OR = 2.648, 95% CI: 1.473-4.760, p = 0.001) in the doctors. The AEFI in all three booster groups are acceptable, and serious adverse events are rare. The risk of AEFI was higher in doctors, which may be related to the high stress during the COVID-19 epidemic. Support from government and non-governmental agencies is important for ensuring the physical and mental health of HCWs.

Analysis of Adverse Effects of COVID-19 Vaccines Experienced by Healthcare Workers at Guizhou Provincial Staff Hospital, China.

Objective: A retrospective survey was conducted of adverse events following immunization (AEFI) experienced by health care workers (HCWs) in a relatively remote ethnic region in southwest China (Guizhou Province) who received COVID-19 vaccines. Methods: From 18 January 2021 to 21 January 2022, all HCWs of Guizhou Provincial Staff Hospital, China, who received at least one dose of inactivated COVID-19 vaccine (Vero cell), recombinant novel coronavirus vaccine (CHO cell), or one dose of adenovirus type-5 (Ad5) vectored COVID-19 vaccine were asked to complete a self-report questionnaire to provide information on any adverse events that may have occurred in the first 3 days after injection. The frequency of AEFI corresponding to the three types of vaccines were compared and the potential risks of AEFI due to the three different vaccines were predicted by multivariate logistic regression analysis. Results: Of the 904 HCWs who completed the survey, the rates of AEFI were 10.1% (80/794) due to Vero cell, 16.3% (13/80) due to CHO cell, and 46.67% (14/30) due to Ad5 vectored vaccines, and the rates were significantly different (χ2 = 38.7, p < 001) between the three vaccines. Multivariate logistic regression models predict that (1) compared to the Ad 5 vectored group, the risk of AEFI occurrence in the Vero cell group was reduced by about 85.9% (OR = 0.141, 95% CI: 0.065–0.306, p < 0.001) and in the CHO cell group by about 72.1% (OR = 0.279, 95% CI: 0.107–0.723, p = 0.009), (2) the odds for women experiencing AEFI were about 2.1 (OR = 2.093, 95% CI: 1.171–3.742, p = 0.013) times as high as those of men, and (3) the risk of AEFI for HCWs with a Bachelor’s degree or above was about 2.2 (OR = 2.237, 95% CI: 1.434–3.489, p = 0.001) times higher than in HCWs who do not have a Bachelor’s degree. Conclusions: 1. The inactivated COVID-19 vaccine (Vero cell), recombinant novel coronavirus vaccine (CHO cell), and adenovirus type-5 (Ad5) vectored COVID-19 vaccine made in China are safe and relatively broad-spectrum. 2. The prevalence of AEFI is more common in women healthcare workers. 3. The risk of AEFI was higher in those with a Bachelor’s degree or above and may be related to the psychological and social effects triggered by the global COVID-19 pandemic.

Adverse Events Following Immunization (AEFI) Reporting in A Rural District in Ghana

Background: Even though vaccines used in routine childhood immunization programmes are safe, adverse events following immunization (AEFI) may occur. These events must be recognized for prompt and effective response. This can contribute to success of the immunization programme and sustain interest of the public in vaccination.Methods: A descriptive cross-sectional study comprising primary and secondary data collection methods were used for the study at Jaman North District in Ghana. The secondary data was extracted from immunization reports using a Microsoft excel spread sheet. The primary data was obtained from respondents using structured interview questionnaire. Simple random sampling was used to select caregivers and health workers were purposively selected. The data was analyzed using Statistical Package for Social Sciences (SPSS) windows (version 21.0).Results: A total of 140 mothers or caregivers and 47 health workers were studied, with mean age of 27.8 years in each group. The rates of AEFI ranged from 0.02% for pneumococcal vaccine to 0.14% for pentavalent vaccine. In all, 63.8% of the health workers could not define AEFI, and 91.5% of the health workers do not use anaphylactic pack at immunization sessions. Majority (95.7%) of the participants agreed that poor AEFIs monitoring can lead to reduction in immunization coverage. AEFI training for health workers had a strong association (p&lt;0.001) on their ability to identify AEFIs. The study indicated that mothers or caregivers were knowledgeable in many of the indicators of AEFI. In all, 93.7% of mothers or caregivers indicated that attitude of health workers was very good.Conclusion: The study revealed low (&lt;1%) AEFI reporting rate by mothers or caregivers. Only 36.2% health workers had knowledge with respect to definition of AFEI. The study indicated that more than a third of mothers (36%) were of the view that reporting of AEFIscan lead to personal consequences. Increased national efforts at surveillance for AEFI is imperative.

COVID-19 Vaccination and the Rate of Immune and Autoimmune Adverse Events Following Immunization: Insights From a Narrative Literature Review.

Despite their proven efficacy and huge contribution to the health of humankind, vaccines continue to be a source of concern for some individuals around the world. Vaccinations against COVID-19 increased the number of distressed people and intensified their distrust, particularly as the pandemic was still emerging and the populations were encouraged to be vaccinated under various slogans like “back to normal life” and “stop coronavirus”, goals which are still to be achieved. As fear of vaccination-related adverse events following immunization (AEFIs) is the main reason for vaccine hesitancy, we reviewed immune and autoimmune AEFIs in particular, though very rare, as the most worrisome aspect of the vaccines. Among others, autoimmune AEFIs of the most commonly administered COVID-19 vaccines include neurological ones such as Guillain-Barre syndrome, transverse myelitis, and Bell’s palsy, as well as myocarditis. In addition, the newly introduced notion related to COVID-19 vaccines, “vaccine-induced immune thrombotic thrombocytopenia/vaccine-induced prothrombotic immune thrombotic thrombocytopenia” (VITT/VIPITT)”, is of importance as well. Overviewing recent medical literature while focusing on the major immune and autoimmune AEFIs, demonstrating their rate of occurrence, presenting the cases reported, and their link to the specific type of COVID-19 vaccines represented the main aim of our work. In this narrative review, we illustrate the different vaccine types in current use, their associated immune and autoimmune AEFIs, with a focus on the 3 main COVID-19 vaccines (BNT162b2, mRNA-1273, and ChAdOx1). While the rate of AEFIs is extremely low, addressing the issue in this manner, in our opinion, is the best strategy for coping with vaccine hesitancy.

Adverse events following introduction of the ChAdOx1 nCoV-19 vaccine in Somalia in 2021: findings from a fragile setting and implications for the future

Vaccination against coronavirus disease 2019 (COVID-19) began in Somalia on 16 March 2021 with the Covishield (ChAdOx1 nCoV-19) vaccine. However, by the end of 2021, only a small percentage of the population had been fully vaccinated. As side effects play an important role in determining public confidence in vaccines and their uptake, this study aimed to examine reported adverse events following immunization (AEFIs) of vaccine recipients. This cross-sectional-survey-based study was conducted between March and October 2021 in Somalia. Vaccine recipients who were eligible to receive the first dose of the Covishield vaccine in the first phase of COVID-19 vaccination were eligible for study inclusion. P<0.05 was considered to indicate significance. Of the 149,985 respondents who had received the first dose of the Covishield vaccine, 378 reported side effects. This represented a reported AEFI rate of 2.5 per 1000 population. Amongst those who reported adverse events, males (2.8 per 1000; P<0.001), respondents aged 35-49 years (3.3 per 1000; P=0.001) and teachers (3.5 per 1000; P=0.000) had higher rates of adverse events compared with females, other age groups and other occupations. Amongst population settlement types, a higher rate of AEFIs was observed amongst refugees (23.9 per 1000; P=0.000) and internally displaced populations (19 per 1000; P=0.000). Nearly half of the vaccine recipients who reported side effects (48%) reported one local symptom, and most symptoms were mild in nature. The probability of having acute and severe side effects was found to be 66% lower among males compared with females [odds ratio (OR) 0.44, 95% confidence interval (CI) 0.26-0.73; P=0.002]. Respondents aged >60 years (OR 1.52, 95% CI 0.64-3.62; P=0.34) were more likely to develop acute and severe AEFIs. None of the study population reported any severe life-threatening symptoms or death. Some variables (sex, profession, age) put recipients at higher odds of acute and severe AEFIs, but the Covishield vaccine generally produced mild side effects in a small proportion of the vaccinated population in Somalia. This study confirms that COVID-19 vaccines are safe, and their benefits clearly outweigh any associated risk.

Description of Frequencies of Reported Adverse Events Following Immunization Among Four Different COVID-19 Vaccine Brands.

IntroductionThe rapid rollout of coronavirus disease 2019 (COVID-19) vaccines for a large proportion of the population necessitates a strong emphasis on safety. Complementary to the existing spontaneous reporting system, The Netherlands Pharmacovigilance Centre Lareb conducted patient-reported cohort event monitoring (CEM).ObjectiveThe primary aim was to investigate differences in the frequencies of any and commonly reported, ‘well-known’, systemic adverse events following immunization (AEFIs) with four COVID-19 vaccines (Pfizer’s Comirnaty®, Moderna’s Spikevax®, AstraZeneca’s Vaxzevria® and the Janssen vaccine). As a secondary aim, we analyzed the frequencies of well-known systemic adverse events after the first and, if applicable, second COVID-19 vaccinations, taking into account age, sex and prior COVID-19 infection.MethodsPatient-reported outcomes (PROs) in the Netherlands starting in February 2021 were analyzed using a prospective cohort design.ResultsData of 27,554 participants who received one vaccination and 20,682 participants who received complete immunization were analyzed. The percentage of patients reporting any AEFI was high and ranged from approximately 53% for the Pfizer vaccine to approximately 94% for the Moderna vaccine. The frequency of serious AEFIs was low, with the highest frequency found for the AstraZeneca vaccine (0.228%). AEFIs were most often experienced by participants receiving the first dose of the AstraZeneca and Janssen vaccines and the second dose of the Moderna vaccine; the Pfizer vaccine was associated with the lowest rate of AEFIs. Participants with a COVID-19 history before vaccination experienced commonly reported systemic AEFIs more frequently after the first vaccination than after the second vaccination. Women and young people experienced more AEFIs than men and older people, respectively.ConclusionsThe analysis of a large cohort provides important information about the rates of AEFIs across age groups, among brands of vaccines and between those with and without prior COVID-19 infection. Participants reported a high number of AEFIs in general, but the frequency of serious AEFIs was low.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40264-022-01151-w.

A Comparison with Adverse Events Following Immunization Associated with Sabin-Strains and Salk-Strains Inactivated Polio Vaccines in Zhejiang Province, China.

Objectives: One dose of Sabin-strains inactivated polio vaccine (IPV) was introduced into the Chinese immunization program on 1 May 2016. This study aimed to evaluate the safety of Sabin-strains IPV and provide a comparison with conventional Salk-strains IPV. Methods: Adverse events following immunization (AEFI) records associated with Sabin-strains IPV and Salk-strains IPV were extracted from the national AEFI surveillance system (NAEFISS) from 1 May 2016 to 31 December 2020. The vaccination information on Sabin-strains IPV and Salk-strains IPV during the same period was obtained from the Zhejiang provincial immunization information system. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories and were compared between Sabin-strains IPV and Salk-strains IPV. Results: In total, 3,861,758 doses of Sabin-strains IPV and 1,018,604 doses of Salk-strains IPV were administered during the study period. The overall AEFI reporting rate for Sabin-strains IPV (3.96/10,000 doses) was significantly lower than that for Salk-strains IPV (5.03/10,000 doses) due to the reporting rate of the minor vaccine product-related reaction following Sabin-strains IPV was significantly lower than that for Salk-strains IPV (2.76/10,000 doses vs. 3.83/10,000 doses). The most frequently reported symptoms/signs were fever, induration/swelling, and rash/urticaria. The most frequently reported serious AEFI with a causal relationship was febrile convulsion, with the reporting rates of 0.10/10,000 doses for Sabin-strains IPV and 0.08/10,000 doses for Salk-strains IPV. No significant difference was found in the reporting rates of the other serious AEFI between the two types of IPV. Conclusion: Most of the AEFI following Sabin-strains IPV and Salk-strains IPV were mild and common adverse reactions. The reporting rate of serious AEFI was not significantly different between Sabin-strains IPV and Salk-strains IPV. Sabin-strains IPV had a favorable safety profile and could be widely used.

Surveillance on the adverse events following immunization with the pentavalent vaccine in Zhejiang, China

ABSTRACT Objectives The aim of this study is to describe the reporting rate of adverse events following immunization (AEFI) with pentavalent vaccine: diphtheria-pertussis-tetanus-poliomyelitis-Haemophilus influenzae type b (DPT-IPV/Hib), and to determine whether the reporting rate of AEFI following DPT-IPV/Hib was higher than the average level of the other vaccines. Methods Review and describe the AEFI reported to national adverse event following immunization surveillance system (NAEFISS) in Zhejiang province from 2015 to 2020. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR‑1.96SE >1 (standard error [SE]) was considered as positive signal. Results NAEFISS received 5726 AEFI reports following DTP-IPV/Hib, with a reporting rate of 20.01/10000 doses. Of the reported AEFI, 202 were serious vaccine product-related reactions, including two cases of anaphylactic shock, five cases of Guillain Barre Syndrome (GBS) and two cases of acute disseminated encephalomyelitis. The reporting rate of fever/redness/induration was the highest among all the clinical diagnosis (14.97/10000 doses). The positive signals were obtained for allergic rash (ROR-1.96SE: 1.36), febrile convulsion (ROR-1.96SE: 1.32) and GBS (ROR-1.96SE: 1.16). Conclusion The present findings bolstered that the DTP-IPV/Hib administered as the four-dose schedule was generally well tolerated in Chinese infants as we did not identify any new/unexpected safety concern from the NAEFISS during a six-year timespan.

Using Population-Based Structures to Actively Monitor AEFIs during a Mass Immunization Campaign—A Case of Measles–Rubella and Polio Vaccines

Active vaccine pharmacovigilance complements the standard passive or spontaneous surveillance system, which suffers from low reporting rates. This study aimed at utilizing population-based structures to report and profile adverse events following immunization (AEFI) with the measles and rubella vaccine (MR), or MR in combination with the bivalent oral polio vaccine (bOPV 1&3) (MR & bOPV), during mass vaccination in Uganda. Caretakers of children at home (less than 5 years) and schoolgoing children were followed up on and encouraged to report any AEFIs on day one, 2–3 days, 10 days, and 14 days after vaccination at school by their teachers and at-home, community-based village health teams. Out of 9798 children followed up on, 382 (3.9%) reported at least one AEFI, and in total, 517 AEFIs were reported. For MR, high temperature (21%), general feeling of weakness (19.3%), and headache (13%) were the most reported AEFIs, though there were variations on the days when they were reported. For the combination dose of MR & bOPV, high temperature (44%), rash (17%), general feeling of weakness (13%), and diarrhoea (8%) were the most common adverse events following immunization reported by caretakers. All 382 children cleared the AEFIs within 2 days, with 343 (90%) children reporting mild or moderate AEFIs and only 39 (10%) reporting severe AEFIs. The reported AEFIs are known and are mentioned in the vaccine leaflets with similar severity classification. Rates of AEFIs differed with the number of days after receiving the immunization. Conclusion: Active surveillance for AEFIs provides additional important information to national vaccine regulatory bodies. It reassures the public that vaccines are safe and that their safety is being taken seriously in Uganda, which would improve vaccine acceptability and confidence in the health system. Piggybacking on existing structures such as village health team members (for children at home) and teachers (for schoolgoing children) facilitates reaching vaccine recipients and increases reporting rates. Therefore, studies using active reporting of AEFIs should be conducted at regular intervals to report the overall incidence of AEs and to monitor trends and changes.

Post-licensure safety monitoring of quadrivalent human papillomavirus vaccine using the national adverse event following immunization surveillance system from Zhejiang province, 2018-2020

ABSTRACT Objectives To evaluate the reporting rate of adverse events following immunization (AEFI) of the quadrivalent human papillomavirus vaccine (4vHPV) and to compare the reporting rate of AEFI following 4vHPV with those following other vaccines. Methods Review and describe the AEFI reported to national adverse event following immunization surveillance system (NAEFISS) in Zhejiang province from 2018 to 2020. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR‑1.96SE >1 (standard error [SE]) was considered as positive signal. Results NAEFISS received 238 reports after receipt of 4vHPV and 899,282 doses of 4vHPV were administered during the study period, with a crude reporting rate of 2.7/10000 doses. Fever/redness/induration (101 reports) was the most common event reported (1.12/10000 doses). Two cases of anaphylactic shock, three cases of Guillain Barre Syndrome and two cases of acute disseminated encephalomyelitis were reported. ROR showed positive signals for seizure (ROR‑1.96SE: 2.1), syncope (ROR‑1.96SE: 1.3), allergic rash (ROR‑1.96SE: 1.6) and headache (ROR‑1.96SE: 2.1). Conclusion The present analysis did not identify new/unexpected safety concerns. Further epidemiological studies are required to systematically validate the data provided by NAEFISS.

Adverse events following ChAdOx1 nCoV-19 Vaccine (COVISHIELD) amongst health care workers: A prospective observational study

BackgroundDuring ongoing COVID-19 pandemic, researchers worked enormously to develop effective vaccines against COVID-19 infection. Two Indian-made vaccines [Covishield (ChAdOx1 nCoV-19) and Covaxin] were granted Emergency Use Authorization. India launched its COVID-19 vaccination drive starting with healthcare workers (HCW). Aim of the study was to evaluate adverse events following immunization (AEFI) amongst the HCW with two doses of Covishield vaccine. We also evaluated association of AEFI according to sex, profession and age groups. MethodsA prospective observational study was conducted in a tertiary care COVID dedicated hospital of Southern India from 16 Jan - 15 Apr 2021. Nine hundred and eighty one HCW who received 2 doses (4 weeks apart) were enrolled. Active and passive surveillance was conducted after 48 hours, and at days 8,15, 22 and 28 for both doses. The rate of AEFI for each dose was determined. Incidence and association of AEFI with various demographic variables was determined. Results1020 non-serious and two serious AEFI (altered sensorium) were reported within 48 hours of first dose. Two hundred and twenty non-serious AEFI were reported within 48 hours of second dose. No AEFI was reported after 15 days for both the doses. We found no association of AEFI with sex and profession ( p >0.5). Significant association of AEFI was found with age ( p <0.01) ConclusionShort-term AEFI were predominantly observed in first 48 hours. Incidence decreased in subsequent weeks with no occurrence after 15 days in both doses. Symptoms were mild in severity and short-lived. No serious AEFI attributable to vaccines were reported.