Does ChAdOx1-S and BNT162b2 heterologous prime-boost vaccination trigger higher rates of vaccine-related adverse events?

Monitoring and active surveillance of adverse events following the booster dose of AZD1222 vaccine in people vaccinated with Sinopharm BBIBP-CorV: a cohort study

BACKGROUND

Given the limited evidence on the side effects of AZD1222 booster in individuals previously vaccinated with Sinopharm BBIBP-CorV, we conducted a cohort event monitoring study to capture adverse events in those receiving AZD1222 booster doses (first or second) after Sinopharm BBIBP-CorV vaccination in Iran.

METHODS

This active COVID-19 vaccine safety surveillance study was conducted in vaccination centers across 12 provinces in Iran. The study population included individuals who had received two doses of Sinopharm BBIBP-CorV and either a first or second AZD1222 booster dose. Each participant was followed for 13 weeks after their booster dose.

RESULTS

A total of 28,742 participants were included, with 13,428 females (46.72%) and 15,314 males (53.28%). The average age was 43.25 ± 14.90 years. Of the total, 82.46% were recruited retrospectively through vaccination registration. Among 16,944 individuals with available polymerase chain reaction test results, 118 tested positive for COVID-19 between 14 and 90 days post-booster. There were 123 hospital admissions, with 18 cases showing a higher likelihood of being associated with adverse events following immunization (AEFIs) or serious adverse events (SAEs). After excluding deaths unrelated to vaccination, four deaths were potentially linked to AEFIs or SAEs. The cumulative incidence rates for hospital admissions and deaths were 106.40 and 13.90 per 100,000 individuals, respectively.

CONCLUSION

The study indicates that AZD1222 booster doses are safe for individuals previously vaccinated with Sinopharm BBIBP-CorV, with rare adverse events and an acceptable safety profile. This supports the use of heterologous booster strategies, though ongoing monitoring and improved pharmacovigilance are essential to detect any potential long-term effects.

Exploring the reported adverse effects of COVID-19 vaccines among vaccinated Arab populations: a multi-national survey study

The coronavirus disease 2019 (COVID-19) pandemic has been a major challenge worldwide for the past years with high morbidity and mortality rates. While vaccination was the cornerstone to control the pandemic and disease spread, concerns regarding safety and adverse events (AEs) have been raised lately. A cross-sectional study was conducted between January 1st and January 22nd, 2022, in six Arabic countries namely Saudi Arabia, Egypt, Syria, Libya, Iraq, and Algeria. We utilized a self-administered questionnaire validated in Arabic which encompassed two main parts. The first was regarding sociodemographic data while the second was about COVID-19 vaccination history, types, doses, and experienced AEs. A multistage sampling was employed in each country, involving the random selection of three governorates from each country, followed by the selection of one urban area and one rural area from each governorate. We included the responses of 1564 participants. The most common AEs after the first and second doses were local AEs (67.9% and 46.6%, respectively) followed by bone pain and myalgia (37.6% and 31.8%, respectively). After the third dose, the most common AEs were local AEs (45.7%) and fever (32.4%). Johnson and Johnson, Sputnik Light, and Moderna vaccines showed the highest frequency of AEs. Factors associated with AEs after the first dose included an increase in age (aOR of 61-75 years compared to the 12-18 years group: 2.60, 95% CI: 1.59-4.25, p = 0.001) and male gender (OR: 0.72, 95% CI: 0.63-0.82, p < 0.001). The cumulative post-vaccination COVID-19 disease was reported with Sinovac (16.1%), Sinopharm (15.8%), and Johnson and Johnson (14.9) vaccines. History of pre-vaccination SARS-CoV-2 infection significantly increases the risk of post-vaccination COVID-19 after the first, second, and booster doses (OR: 3.09, CI: 1.9-5.07, p < 0.0001; OR: 2.56, CI: 1.89-3.47, p < 0.0001; and OR: 2.94, CI: 1.6-5.39, p = 0.0005 respectively). In conclusion, AEs were common among our participants, especially local AEs. Further extensive studies are needed to generate more generalizable data regarding the safety of different vaccines.