Rujittika Mungmunpuntipantip1, Viroj Wiwanitkit2. 1. Private Academic Consultant, Bangkok, Thailand. Electronic address: rujittika@gmail.com. 2. Honorary Professor, Dr DY Patil University, Pune, India.
Dear Editor,We would like to comment on the article “Serological response and safety of heterologous ChAdOx1-nCoV-19/mRNA-1273 prime-boost immunization with a twelve-week gap,” we would like to provide our comments. According to Sheng et al., adverse effects following the boost dosage were modest and temporary. The 12-week interval group showed greater neutralizing antibody titers against SARS-CoV-2 variants than the 4-week interval group and was comparable to the 8-week interval group at day 28. The findings, according to Sheng et al., supported the flexible deployment of viral vectored and mRNA vaccines at intervals of between 8 and 12 weeks. We both believe that using mRNA and viral vectored vaccinations in flexible schedules has benefits. However, it should carefully consider how to interpret the findings in this report. At the very least, we should be aware of the potential consequences of past asymptomatic COVID-19, which is a prevalent issue. The prior asymptomatic COVID-19 may have affected the observed immune response outcome, thus it is important to rule out its influence.
Declaration of competing interest
The authors have no conflicts of interest relevant to this article.