Abstract
The coronavirus disease 2019 (COVID-19) pandemic has become a severe healthcare problem worldwide since the first outbreak in late December 2019. Currently, the COVID-19 vaccine has been used in many countries, but it is still unable to control the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, despite patients receiving full vaccination doses. Therefore, we aimed to appraise the booster effect of the different platforms of vaccines, including inactivated vaccine (BBIBP), viral vector vaccine (AZD122), and mRNA vaccine (BNT162b2), in healthy adults who received the full dose of inactivated vaccine (CoronaVac). The booster dose was safe with no serious adverse events. Moreover, the immunogenicity indicated that the booster dose with viral vector and mRNA vaccine achieved a significant proportion of Ig anti-receptor binding domain (RBD), IgG anti-RBD, and IgA anti-S1 booster response. In contrast, inactivated vaccine achieved a lower booster response than others. Consequently, the neutralization activity of vaccinated serum had a high inhibition of over 90% against SARS-CoV-2 wild-type and their variants (B.1.1.7–alpha, B.1.351–beta, and B.1.617.2–delta). In addition, IgG anti-nucleocapsid was observed only among the group that received the BBIBP booster. Our study found a significant increase in levels of IFN-ɣ secreting T-cell response after the additional viral vector or mRNA booster vaccination. This study showed that administration with either viral vector (AZD1222) or mRNA (BNT162b2) boosters in individuals with a history of two doses of inactivated vaccine (CoronaVac) obtained great immunogenicity with acceptable adverse events.
Highlights
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the family of coronaviruses in the genus of Betacoronavirus
Thailand had begun to inoculate most of the population with an inactivated vaccine (CoronaVac; Sinovac Life Sciences, Beijing, China), mainly since the end of February 2021, before the arrival of the viral vector vaccine, AZD1222 (University of Oxford/AstraZeneca, Oxford, UK), from Siam bioscience (AstraZeneca (Thailand) Co., Ltd., Nonthaburi, Thailand)
AZD1222 regimen, one participant was excluded as they developed SARS-CoV-2 infection, which was validated by nasopharyngeal swab and real-time polymerase chain reaction on day 7 after vaccination
Summary
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the family of coronaviruses in the genus of Betacoronavirus. SARS-CoV-2 is rapidly transmitted as airborne contagious droplets when in close contact with an infected carrier. Beginning of the coronavirus disease 2019 (COVID-19) outbreak in Wuhan, China, in December 2019, this virus had been dramatically transmitted worldwide. Organization (WHO) declared COVID-19 a pandemic on 11 March 2020. As of the COVID-19 vaccination has been administered on a global scale. Thailand had begun to inoculate most of the population with an inactivated vaccine (CoronaVac; Sinovac Life Sciences, Beijing, China), mainly since the end of February 2021, before the arrival of the viral vector vaccine, AZD1222 (University of Oxford/AstraZeneca, Oxford, UK), from Siam bioscience (AstraZeneca (Thailand) Co., Ltd., Nonthaburi, Thailand). Thailand launched the first mass vaccination program with many vaccines during June
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