A Survey of Events Following COVID-19 Vaccination in Bengaluru, Karnataka

Introduction

Since the start of the pandemic, there has been a desperate need for a vaccine against COVID-19. On January 16, 2021, India rolled out its ambitious effort to vaccinate its population of 1.3 billion. But currently, we are unaware of the post-vaccination experience in the real world outside of the well-controlled clinical trials. Awareness regarding vaccination will help to educate the public, solve false information and reduce vaccine hesitancy. Hence, this survey was conducted to know the immediate events to the first dose of the COVID-19 vaccine and to study the profile of post-vaccination symptoms for individual vaccines.

Materials and Methods

A cross-sectional study was conducted including questions related to the immediate post-vaccination experience. The ^1st phase of vaccination prioritised healthcare workers to receive the first dose. The survey was sent to beneficiaries who received the COVID-19 vaccine till February 28, 2021. Questions were framed in a binary fashion, with open-ended questions on symptom profile and other outcomes that further fit the experience. The data was collected through an online survey. All the data were entered in Microsoft Excel and analysed using SPSS version 20.00.

Results

A total of 2396 vaccine beneficiaries answered the survey over one week from 16^th January to 28^th February 2021. Majority of the participants who responded to the survey were doctors (75.8%), followed by nurses (16.2%) and other health care workers (8%) (Figure 1). This does not essentially replicate the proportion of beneficiaries who received the vaccine. 56% of the participants were males and the rest 44% were females. Among the participants, 88% had received Covishield (Astra-Oxford vaccine by Serum Institute of India) and 12% received Covaxin (Bharat Biotech, India) (Figure 2)

Among the respondents, 45.9% reported at least one symptom. Tiredness (45%), myalgia (44%), fever (34%), headache (28%), local pain at the injection site (27%), joint pain (12%), nausea (8%) and diarrhoea (3%) were the most common symptoms. All the other symptoms were less than 1% (Figure 3). The likelihood of having symptoms reduced with advancing age (Figure 3). The frequency of symptoms was 71% (3rd decade or 20-29 years), 62% (4^th decade or 30-39 years), 58% (5^th decade), 51% (6^th decade), 32% (7th decade) and 17% (8th decade) (Figure 4).

Post-vaccination symptoms were seen more commonly in women (74.7%) compared to men (58.6%) (p < 0.001); this observation was constant across all the age groups. Women were more likely to report symptoms severe enough to stop working for a day (27% vs. 15%), had to take pain relievers (70% vs. 51%) and developed symptoms slightly earlier (10 hours after vaccination) than men (12 hours) (p < 0.001). It was also reported that they had longer duration of symptoms (30 hours vs. 28.5 hours, p = 0.01).

Older people had delayed onset of symptoms, happening at an average of 13.4 hours (70-79 years), compared to 10 hours in younger age groups (20-29 years) following vaccination (p <0.001). The duration of symptoms decreased with advancing age, ranging from an average of 28.8 hours in younger age groups (20-29 years) to 22.9 hours in older age groups (70-79 years) (p <0.001). Symptoms were noticed within the first 12 hours in 79%.

A history of infection with COVID-19 was reported by 8.7%. Their symptom profile was not different to those who did not have a history (Table 1). The frequency of experiencing symptoms was 46.6% for Covishield and 25% for Covaxin. As only 12% of the respondents received Covaxin, a direct comparison was not feasible.

Discussion

Symptoms such as tiredness (45%), followed by myalgia (44%), fever (34%), headache (28%) and pain at the injection site (27%) were most commonly reported. Nearly half of respondents reported mild symptoms which are mostly predictable following vaccination and no serious symptom that required hospitalization was reported during the time of the study. Symptoms appeared within the mean duration of 30 hours. The symptom severity was as expected or milder in 90% of the population and only 20% felt that it was severe enough to affect work the next day. While 71% developed symptoms between the age group of 20-29 years, only 17% above 70 years reported any symptoms. Vaccine reactogenicity is not considered a definitive sign of immune response though it is known to be related to a transient rise in inflammatory cytokines.¹ In our study, post-vaccination symptoms were more often seen in women compared to men. It was also observed that the onset of symptoms was earlier and duration of symptoms was prolonged in the fairer sex. This observation was consistent across all the age groups. In the phase 2/3 trial of Astra-Oxford ChAdOx1 nCoV-19, at least one systemic symptom was reported following vaccination with the standard dose; by 86% of participants in the 18–55 years group, 77% in the 56–69 years group, and 65% in the 70 years and older group.² The findings of the present survey correlated with results from published trials of vaccines. While discussing post-vaccination experience, it is interesting to note that placebo injections produced comparable symptoms. This study did not quantify post-vaccination antibody response. Hence, it is  not possible to infer whether the muted post-vaccination symptoms among older people was a sign of immune senescence. Although symptoms are known to correlate with neutralising antibody levels during COVID-19,⁵ the presence of symptoms following vaccination does not dependably predict antibody response.⁶ The frequency of using paracetamol decreased from 71% in the 20-29 years age group to 16% in the 80-90 years age group. This interrelated with the frequency of symptoms in the subgroups. Although the use of paracetamol to decrease post-vaccination discomfort is considered acceptable,⁷ routine prophylactic use of pain-relievers is not recommended as there is evidence of blunted immune response as a result.^7,8 Fear of the unknown is the main reason for vaccine hesitancy. By educating such people on what to expect, the findings of this study will be supportive to those who are fearful of the new vaccine. The element that post-vaccination symptoms were mild, expected and short-lived will help reduce vaccine hesitancy.

Limitations

Limitations of this study were that it was conducted in English, with no scope for reporting delayed symptoms. As the number of Covaxin respondents were less, it was difficult to make a comparison with Covishield. Also, as with any survey, it is more likely that those affected by the vaccine or medication would have answered the survey more compared to those not affected by the vaccine.

Conclusion

The majority of healthcare professionals who finished the survey reported that the symptoms met their expectations. The most commonly reported symptoms included myalgia, tiredness and fever and in 90% of the participants, the symptoms were mild and no serious events were reported during the time this study was conducted. The younger age group was more commonly affected by symptoms after vaccination. From this study, we could conclude that a history of COVID-19 lead to no difference in symptoms.