Mix-and-match COVID-19 vaccination: a proper strategy for countries of COVID-19 vaccine shortage

Abstract

A comprehensive search was carried out in mainstream bibliographic databases or Medical Subject Headings, including ScienDirect, PubMed, Scopus, and ISI Web of Science. The search was applied to the articles that were published between January 2021 and November 2021. With strict literature search and screening processes, it yielded 10 articles from 136 articles of initial literature database. In June 2021, a preliminary study conducted by the University of Oxford scientists demonstrated that mixing the AstraZeneca and Pfizer vaccines produced a robust immune response against the SARS-CoV-2 (COVID-19) virus and induced higher antibodies than an only two-dose schedule of AstraZeneca vaccine and none of the groups demonstrated decreased neutralizing activity against the Alpha variant (UK variant), but the neutralization titer reduced by 2.5 to 6times against the Beta variant (South African variant), Gamma variant (Brazilian variant), and Delta variant (Indian variant). The Comparing COVID-19 Vaccine Schedule Combinations (Com-COV) study (463 cases of the 4-week interval group) revealed that immunization with AstraZeneca vaccine followed by Pfizer vaccine at the 4-week interval demonstrated a better immune response out of the two mixed dosing regimens. Com-COV study demonstrated in the earlier phase that around 30 % to 40 % of those who received mixed doses reported fevers after their second jab, compared to 10 % to 20 % of those who received the same vaccine for both doses. This result could be attributable to the shorter, 4-week interval between doses that was used during the Oxford study, whereas the safety data from a cohort with a 12-week dosing interval is still to appear. In conclusion, it is better to give a different COVID-19 vaccine or mix-and-match COVID-19 vaccination than not administer the second dose at all.