Assessment of adverse events among healthcare workers following the Janssen COVID-19 vaccine in Tigray, Ethiopia (2024)

Abstract

Apart from the inequality in vaccination, war zones and areas where communication is disrupted are affected by myths and misconceptions about COVID-19 vaccines, heightening vaccine hesitancy. Local data on adverse eventsof the vaccines and their mildness can increase confidence and acceptance of the vaccines in the respective population. In areas of conflict and communication blackouts, the perception of the vaccines by health workers is of paramount importance as public health recommendations may not reach the public. Therefore, the scientific evaluation of adverse events following COVID-19 vaccination in such areas is invaluable. This cross-sectional, facility-based study was conducted using a structured, interviewer-administered questionnaire to assess the adverse events experienced by healthcare workers who received the Janssen COVID-19 vaccine. The sample was divided proportionally to the number of vaccinated healthcare workers for the different healthcare professions, and participants were then randomly selected from each profession. Prior to data collection, a pilot test was conducted with 5% of the sample size outside the selected hospital. The study was conducted using a structured questionnaire completed by an interviewer to assess adverse events in 442 healthcare workers who had received the Janssen COVID-19 vaccine between July 11 and 25, 2022. The study period was from August 15 to September 15, 2022. A significant number of healthcare workers [366 (83.3%); 95% CI 79.5%, 86.5%] experienced at least one adverse event. Nearly 90% of participants reported that the adverse events were mild to moderate. Pain at the injection site [307 (69.5%); 95% CI 65.0%, 73.6%] and headache [247 (55.9%); 95% CI 51.2%, 60.4%] were the most common local and systemic adverse events, respectively. Two HCWs experienced anaphylactic reaction. Younger age was significantly associated with the occurrence of adverse events. We deciphered that the adverse events reported by the study participants were not different from the typically occurring vaccine-related adverse reactions, and therefore concluded that post-vaccination reactions in healthcare workers were minor. Although vaccination in Tigray is currently stalled due to the siege, responsible stakeholders should develop a mechanism to track population-wide adverse events once the vaccines start to rollout.

Introduction

Mass vaccination is the most promising means of combating respiratory diseases caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). To date, the US Food and Drug Administration (FDA) has granted emergency use authorization for the Pfizer-BioNTech (BNTb262), Moderna (mRNA-1273), and Janssen COVID-19 (Ad26.COV2.S) vaccines¹. Phase 3 clinical trials have shown that Pfizer-BioNTech and Moderna are 95% and 94.1% effective, respectively, in preventing coronavirus disease2019 (COVID-19)^2,3. Janssen’s COVID-19 vaccine and other adenovirus-based vaccines have also achieved good results in preventing the infection. The efficacy of the Janssen COVID-19 vaccine in preventing severe critical illness is 77% at least 14days after administration, and increases up to 85% at least 28days after administration⁴. In general, clinical studies have shown that COVID-19 vaccines have an efficacy of 70.4–95% in preventing symptomatic COVID-19 infection⁵. As of January 2023, more than 13 billion COVID-19 vaccinations have been administered worldwide. However, the distribution is lopsided, with less privileged countries such as those in Africa lagging behind in vaccination coverage⁶.

Despite the success of vaccines, concerns about adverse events (AEs) have been a major barrier to vaccination worldwide⁷. According to the definition of Herve et al., vaccine reactogenicity is “a subset of reactions that occur soon after vaccination and are a physical manifestation of the inflammatory response to vaccination⁸, while the WHO defines AEs as “any untoward medical occurrence which follows immunization and which does not necessarily have a causal relationship with the usage of the vaccine”⁹.

In addition to unavoidable mild and transient AEs such as local pain/redness/swelling at the injection site, and general side effects such as fatigue, muscle/joint pain, headache, chills/fever and nausea¹⁰, several myths and misconceptions related to vaccines, such as associated disabilities like infertility, COVID-19 infection, DNA mutation and death, pose a serious challenge¹¹. A strong antipathy towards vaccines was observed following a worldwide warning due to cases of serious AEs such as thrombosis with thrombocytopenia syndrome (TTS) associated with Janssen's COVID-19 vaccine and other COVID-19 vaccines¹². This forced the FDA to briefly suspend Janssen's COVID-19 vaccine¹³. However, this stance was immediately reversed as the vaccine performed well in preventing severe disease, and TTS and associated deaths were rare, affecting only eight people per 8 million doses¹⁴.

Areas where communication is interrupted are most affected by hearsay about vaccinations. The difficulty of accessing scientifically sound information and the disintegration of the health information system make it difficult to correct erroneous conclusionsabout vaccines¹⁵. The resulting reluctance to vaccinate is leading to the unchecked spread of COVID-19 infections¹⁶. The impact is even worse in war zones which already suffer from vaccine inequity¹⁷.

Tigray, a region in northern Ethiopia, has been largely excluded from COVID-19 vaccination campaigns due to a war that broke out in November 2020 and a subsequent siegeimposed in June 2022¹⁸. Unpublished data from the region’s regional health office shows that only 2% of the population had received a single dose of the AstraZeneca vaccine in around May 2021. After that, only the residents of Mekelle, the capital of Tigray, were vaccinated in a two-week campaign from July 11 to July 25, 2022. The communication blackout and the widespread destruction of the health information system in the region are the biggest obstacles in debunking the myths and misconceptions surrounding the COVID-19 vaccines that are preventing the trickle of vaccines that have arrived in Tigray from reaching the population¹⁹.

Healthcare workers (HCWs) play an indispensable role in building public confidence in vaccines. Patients also rely on HCWs for information about vaccine-related AEs²⁰. Therefore, vaccine hesitancy is particularly high when HCWs, who are expected to lead the campaign, are reluctant²¹. This not only puts a strain on vaccination campaigns, but also leads to significant morbidity and mortality as unvaccinated professionals transmit the virus to the most vulnerable during patient care¹⁶. Although the JanssenCOVID-19 vaccine is currently being withdrawn by the Food and Drug Administration (FDA) at the request of the manufacturer due to expiration of the license and lack of demand in May 2023, it is considered necessary to provide local data on AEs of the vaccine²². Conducting a Janssen COVID-19vaccine AEs evaluation in HCWs is critical for several reasons. It is important to understand the AEs of the vaccine in different global and regional contexts, taking into account factors such as population demographics and healthcare infrastructure. Conducting global, regional and local studies helps to identify specific patterns of AEs, differences in reporting, and the influence of HCWs characteristics on vaccine reactions. By synthesizing the information from the study, we can make informed decisions about vaccination strategies, risk communication, and targeted interventions related to AEs among HCWs at the local level (Supplementary Information).

Therefore, it is essential to assess the prevalence of AEs in HCWs after vaccination to reduce any barriers to vaccination. However, reports of AEs are mostly concentrated in industrialized countries. There are hardly any reports from Africa and war zones²³.

The war tornTigray also lacks data on AEs related toCOVID-19 vaccinesincluding the Janssen COVID-19 vaccine. Combined with the communication breakdown and the collapse of the health information system, this leads to low vaccination coverage, hence, a study on this issue is needed. We hypothesized that a substantial proportion of HCWs will experience AEs, most of which will be mild in nature, such that avoiding the vaccine would not be justified. Therefore, the aim of this study was to investigate the magnitude and severity of AEs following vaccination with the Janssen COVID-19 vaccine among HCWs at Ayder Comprehensive Specialized Hospital (ACSH), Tigray, Ethiopia.

Materials and methods

Results

Discussion

By conducting a cross-sectional study on HCWs, we were able to determine that the majority of study participants experienced AEs after the Janssen COVID-19 vaccine. However, the AEs were largely perceived to be generally mild, neither requiring treatment nor staying for more than 24h. Being young was significantly associated with having at least one AE. Our results support the safety profile of the Janssen vaccine, and could be used to build confidence in vaccine uptake in Tigray region.

In view of the success of the current vaccines against COVID-19 worldwide, it can therefore be concluded that the benefits outweigh the risks.

Most participants reported that they had experienced at least one AE after vaccination with the Janssen COVID-19 vaccine. The development of AEs as a result of vaccine reactogenicity due to the inflammatory response to vaccine components is a relatively common scenario²⁵. In studies by Klugar M et al. and Agnes Kant et al. 88% and 82% of study participants reported AEs, respectively^26,27. Similarly, as reported by Bijay Bhandari et al. in their report on AEs following administration of Janssen's COVID-19 vaccine, injection site pain and headache were the most common local and systemic AEs, observed in our study, respectively⁹. These findings support the results of the clinical trials conducted to evaluate the safety and efficacy of the Janssen COVID-19 vaccine⁴.

Most of the AEs experienced by the study participants were perceived as mild to moderate. Other studies also support our findings. A Jordanian study examining the side effects of vaccines in HCWs found that most reported side effects were of mild to moderate severity²⁸. An online survey in Valencia, Spain, also found that the majority of side effects reported by study participants were mild to moderate in severity²⁹. Janssen's COVID-19 vaccine has been associated with several serious AEs, including thrombosis with thrombocytopenia syndrome and anaphylactic reaction^8,30. No hospitalizations, deaths, or other serious AEs occurred in our study, with the exception of two HCWs who reported anaphylactic reaction, four participants who developed a urticarial- like reaction, and one person who reported transient arm weakness. None of the AEs that occurred were reported to the immunization program or the Ethiopian Food and Drug Administration. This is a testament to the war related disintegration of health infrastructure and surveillance system in the region. Following a safety review, the FDA and the U.S. Centers for Disease Control and Prevention determined that Janssen's COVID-19 vaccine is safe and can be administered as an alternative to Pfizer and Moderna in certain populations³¹. The current study supports this position, although it is important to note that due to the small sample size in this study, it is difficult to draw conclusions about the actual prevalence of serious AEs associated with the Janssen COVID-19 vaccine. The efficacy of the vaccine in preventing moderate to severe COVID-19 infections, hospitalizations and deaths is acceptable⁴. Although adenovirus-based vaccines such as the Janssen vaccine have lower efficacy compared to mRNA-based vaccines, they are less expensive and less demanding to store¹². Therefore they constitute a better option in resource-limited settings like our setup, and can play a pivotal role in curtailing the pandemic.

In line with other studies, a significant proportion of participants reported that their symptoms did not warrant treatment. An analysis of a large data pool from the United States Vaccine Adverse Effect Reporting System Data by Amninder Singh et al. found that most of the solicited AEs did not require treatment³⁰. In the current study, most ofthe AEs occurred within one day of vaccination, and no participant reported onset of AEs later than three days after vaccination. Furthermore, AEs were transient, and disappeared within one day in the majority of the HCWs. These results are consistent with those of Lounis et al. and Chongliang et al. In these studies, most AEs occurred within 24h of vaccination, and did not last longer than 48h^32,33. Our results suggest that the AEs reported after taking the Janssen COVID-19 vaccine were not alarming, and do not call into question the need for vaccination. In light of these findings, it is essential to encourage HCWs in particular and the population in general to get vaccinated, and follow the vaccination recommendations. This is necessary and should be emphasized especially in areas with communication deficits, where misconceptions about vaccines can be taken at face value because guidelines and expert recommendations have difficulty reaching the public.

This study showed that younger age was significantly associated with at least one AE. Several studies have shown that aging decreases the immune response²⁹. Therefore, our finding is not surprising, as the AEs that occurred after vaccination in this study were largely due to immunologic reactogenicity. A study conducted among dentists in the United States corroborates our findings and reports that more AEs occurred in individuals younger than 55years¹⁰. As the elderly are at a significant risk of morbidity and mortality due to COVID-19, it is encouraging that the current vaccines against COVID-19 are safer in the elderly population.

In our study, however, no significant correlation was found between gender and the occurrence of AEs. This is in contrast to other studies that show a significant association between female gender and the occurrence of AEs. An online survey in Spain found that female gender was associated with a significant risk for the occurrence of AEs after administration of the Janssen COVID-19 vaccine³⁴. In addition, variables such as previous COVID-19 infection and previous vaccination with other COVID-19 vaccines were not found to be significantly associated with the occurrence of AEs, although other studies have found a significant association between these factors and the occurrence of AEs after COVID-19 vaccination²⁷. The small sample size may have downplayed the role of sex and other variables as important factors in the development of AEs in our study. Although vaccination in Tigray is currently stalled due to the siege, we recommend that the Tigray Regional Health Bureau and other humanitarian organisations develop a mechanism for population-wide tracking of AEs and associated factors once vaccine rollout begins.

This study will play an important role in combating the myths and misconceptions circulating around COVID-19 vaccines and convincing the general population of the importance of vaccination in combating the COVID-19 pandemic under the conditions of communication blackout and collapse of the health information system in Tigray, Northern Ethiopia. The data in our study was collected in person, unlike most studies where AEs were recorded online. This creates a room for recording symptoms that may not be easily recognized by study participants, especially those with lower levels of education. However, our study also has its limitations. Given the time gap between the days of vaccination and data collection, and the fact that the study is based on self-reported AEs , participants may not have provided accurate information on AEs due to recall errors. In addition, the study did not include follow-up for the occurrence of medium- and long-term AEs of the vaccine. Furthermore, the generalizability of the study could be impaired as only medical personnel were involved, the participants were young, and the study was conducted in only one institution. In addition, cross-sectional studies cannot establish a cause–effect relationship between the administration of the vaccine and AEs, as it is a snapshot in nature, which may lead to recall bias and under- or over-reporting of AEs. The study population may not be representative of all HCWs and the general population in the region, leading to potential bias in the results. Cross-sectional studies may also not capture delayed or long-term AEs due to the short-term nature of the observations.

This study also assumes that the HCW population was homogenous in terms of demographics, health status, and vaccine acceptance, which may not always be the case. It also assumes that participants accurately report their AEs without intentional or unintentional misrepresentation and any AEs observed are directly attributable to the Janssen vaccine without considering other confounding variables.

Conclusions

This study found that most of the study participants experienced AEs following administration of the Janssen COVID-19 vaccine. The most common local AE was pain at the injection site, while headache predominated among the systemic AEs. Younger age was significantly associated with the occurrence of AEs. The majority of study participants reported that most AEs were mild to moderate in severity. In addition, most AEs were transient and did not require medical attention.

Overall, our study has shown that the vaccine is associated largely with minor AEs. We therefore recommend that HCWs in particular and the population in general be vaccinated.

Supplementary Information

Acknowledgements

All of the authors are grateful for the support received from Ayder Comprehensive Specialized Hospital; and for the study participants who consented to be included in the study.

Author contributions

B.T.A.: Conceptualization of the study. E.B., H.T., B.T.A., M.A.G., D.Z. and A.H.: Data collection and entry. B.T.A. and H.E.A.: Data cleaning. H.E.A.: Data analysis. B.T.A.: Manuscript writeup. H.T., B.T.A., A.H., E.B., M.A.G. and D.Z.: Manuscript reviewing and editing. All authors have read and agreed to the published version of the manuscript.

Data availability

All data relevant to the study are included in the manuscript or can be shared upon request. The corresponding author can be contacted in case someone wants to request the data from this study.

Competing interests

The authors declare no competing interests.

Footnotes

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-024-53561-8.

References

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.