This project aims to monitor the side effects of COVID-19 vaccines worldwide actively. The primary objectives of the project include a) to estimate the prevalence of each local and systemic side effect of each COVID-19 vaccine among healthcare workers (HCW), old adults over +65 (OA), and schoolteachers (ST); b) to evaluate the potential demographic and medical risk factors for side effects frequency and intensity; c) to evaluate the long-term consequences of COVID-19 vaccines. The secondary objectives include a) to evaluate the relative safety of COVID-19 vaccines compared to each other; b) to evaluate the impact of palliative drugs used by the recently vaccinated individuals on their short-term side effects resolution.

Introduction:

COVID-19 vaccines are the foremost asset to overcome the ongoing pandemic; therefore, mass vaccination has become a high priority for the world's governments. While vaccination strategies need to be accelerated to minimise daily fatalities and relieve the pandemic's economic burdens, vaccine hesitancy (VH) remains a serious challenge for these efforts. VH refers to "delay in acceptance or refusal of vaccines despite availability of vaccine services",; and it is an emerging public health challenge nourished by misinformation related to vaccines effectiveness and safety. Aversion to vaccines' potential side effects is the most frequent cause of VH among population groups. Therefore, a recent systematic review revealed that raising public awareness of vaccines' effectiveness and side effects is vital for improving vaccine uptake.

Public health systems globally experience a novel and unique challenge due to the variety of vaccines manufacturers and the high levels of public awareness about those manufacturers and their marketing strategies. This unprecedented situation is predicted to create what we can refer to as "vaccine selectivity, " increasing the pressure on our weakened health systems and economies and increasing vaccine hesitancy levels. Independent (non-sponsored) studies with rigorous methods can perfectly lead the pharmacovigilance efforts of COVID-19 vaccines globally. Given their independent nature and transparent design, these studies can play a key role in suppressing vaccine hesitancy levels by enhancing public confidence in vaccines.

Design

This project comprises two phases; a) a cross-sectional survey for the short-term side effects of COVID-19 vaccines; b) a prospective cohort study for the long-term safety of COVID-19 vaccines.

Phase A:

A validated self-administered questionnaire will be developed and delivered online to the target population groups (HCW, OA & ST). The questionnaire will be inquiring about the short-term side effects that emerged within 30 days following the vaccine shot (either the first or the second dose). The side effects will be classified as local or systemic, and their onset, duration, and intensity will be self-assessed and self-reported by the respondents. This phase is proposed to take place until December 31st, 2021.

Phase B:

A validated self-administered questionnaire will be developed and delivered online to the volunteers who participated in Phase A and expressed their interest to report their long-term side effects. In this phase, the vaccine effectiveness and side effects will be evaluated after booster doses. Phase B will take place for five consecutive years starting from 2022.

Inclusion Criteria:

• HCW, OA and ST who received COVID-19 vaccine.
• Participating subjects should be at least 18-year-old and able to give their informed consent independently.

Exclusion Criteria:

• Non HCW, OA and ST who received the COVID-19.

In Phase A, a pragmatic approach will track each target group according to the governmental plan; in most countries, it went from HCW to OA to ST. The sample of Phase B will be pre-identified based on the outcome of Phase A. If ≥ 25% of HCW, 10% of OA and 10% of ST of Phase A showed their interest to join Phase B, no additional recruitment will be required. If < 25% of HCW, 10% of OA and 10% of ST of Phase A showed their interest in Phase B, additional recruitment will be carried out targeting healthcare workers who will receive booster doses. In case of the emergence of special side effects after booster doses, additional recruitment of healthcare workers will be required.