Mix and Match of COVID-19 Vaccines and the Importance of Protein Based Boosters

Coronavirus disease 2019 (COVID-19) is the highly viral infectious disease caused by the severe acute respiratory syndrome 2 (SARS-CoV-2) virus (WHO, 2021). As of 5 August 2022, more than 587 million people had already been infected with around 6.4 million deaths (https://ourworldindata.org/covid-vaccinations, 5 August). After the alpha, beta, gamma, and delta variants, the omicron (B.1.1.529) was emerged in Botswana. The original variant of omicron was named as B.1 and following the original BA.1 variant, several subvariants of Omicron have detected: BA.2, BA.3, BA.4, and BA.5 (Yao et al., 2022). Although the data related to the sub-variants before BA.5 show that the percentage of hospitalization due to Omicron has decreased compared to the previous variants (alpha, beta, gamma and delta), but the coronavirus is still considered as a serious threat to humans.