# Changing Dynamics of SARS-CoV-2: A Global Challenge
## 6 Impact of Variants on the Vaccines
A mixed vaccination strategy is now being tested in several countries to combat SARS  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{3}{*}{**Name of Vaccine**} & \multirow{3}{*}{**Vaccine Type**} & \multicolumn{3}{c}{**Efficacy**} & \multicolumn{3}{c}{**Effectiveness against Variants**} \\  & & & **First Dose** & **Second Dose** & **B.1.351/beta (South Africa), P.1/gamma (Brazil), B.1.617/delta (India))** \\ \hline \hline \multirow{3}{*}{Pfizer-BioNTech (BNT162b2)} & \multirow{3}{*}{mRNA} & \multirow{3}{*}{92.6\%} & \multirow{3}{*}{95.0\%} & Alpha (B.1.1.7)–87.0\% \\  & & & & Beta (B.1.351)–75.0\% \\  & & & & Gamma (P1)–82.0\% \\  & & & & Delta (B.1.617.2)–95.0\% \\ \hline \multirow{3}{*}{Moderna (mRNA-1273)} & \multirow{3}{*}{mRNA} & \multirow{3}{*}{81.6\%} & \multirow{3}{*}{94.1\%} & Alpha (B.1.1.7)–81.6\% \\  & & & & Beta (B.1.351)–95.7\% \\  & & & & Gamma (P1)–89.0\% \\  & & & & Delta (B.1.617.2)–95.0\% \\ \hline \multirow{3}{*}{AstraZeneca, University of Oxford (AZD1222)} & \multirow{3}{*}{Adenovirus-based} & \multirow{3}{*}{90.0\%} & \multirow{3}{*}{62.1\%} & Alpha (B.1.1.7)–70.4\% \\  & & & & Beta (B.1.351)–77.0\% \\  & & & & Gamma (P1)–82.0\% \\  & & & & Delta (B.1.617.2)–67.0\% \\ \hline \multirow{3}{*}{Johnson \& Johnson \& Johnson vector & 66.0\% & 73.1\% & Alpha (B.1.1.7)–74.0\% \\  & & & & Beta (B.1.351)–52.0\% \\  & & vector & & Gamma (P1)–66.0\% \\  & & & & Delta (B.1.617.2)–60.0\% \\ \hline \multirow{3}{*}{BBIBP-CorV} & \multirow{3}{*}{Inactivated virus vaccine} & \multirow{3}{*}{79.0\%} & \multirow{3}{*}{[PERSON] efficacious in preventing PCR-confirmed COVID-19 in adults. No vaccine effectiveness studies yet to inform protection against variants of concern (CDC, 2021)} \\  & & & & & Alpha (B.1.1.7)–86.3\% \\  & & & & Beta (B.1.351)–51.0\% \\  & & & & Non-B.1.1.7–96.0\% \\ \hline \multirow{3}{*}{Novavax (NVX-CoV2373)} & \multirow{3}{*}{Protein-based vaccine} & \multirow{3}{*}{83.4\%} & \multirow{3}{*}{89.7\%} & Alpha (B.1.1.7)–70.4\% \\  & & & & Non-B.1.1.7–81.5\% \\ \cline{1-1}  &  
CoV-2 infections [89]. Currently, a mix-and-match approach using COVID-19 vaccines administered as heterologous prime-booster doses are being tested in the UK to estimate the effectiveness of Moderna (mRNA-1273), Pfizer (BNT162b2), Oxford (AZD1222) and Novavax (NVX-CoV2373) vaccines in 'Com-Cov2 trial', and Oxford and Pfizer vaccines in 'CombivacS trial' in Spain [95]. With the appearance of different strains of SARS-CoV-2, a multivariant vaccine could also be developed. Additionally, COVID-19 can be prevented by using trivalent as well as quadrivalent vaccines, which target three and four strains of the virus, respectively [83]. COVID-19 could be addressed with a significant modification in immunization policies and through the implementation of the suggested approaches. We need to understand that an individual with partial protection conferred from vaccines is better off than an individual without any protection. However, the problem of whether vaccine development would be able to keep up with the evolution of the virus still remains unsolved [96].