Table 4. Advantages and Limitations of Different Types of Vaccines.

MERS-CoV: Middle East respiratory syndrome coronavirus

	mRNA vaccines [mRNA-1273 (Moderna) & BNT162b2 (Pfizer)]	Vector-based vaccines [Ad26.COV2.S (Johnson and Johnson)]
Advantages	1) Translation of mRNA occurs in the cytosol of the host cell averting the risk of any sort of integration into the host genome	1) Avoids handling of any infectious particle and it has been used widely for MERS-CoV with positive results from the trials 2) Show a highly specific gene delivery into the host cell with a vigorous immune response
Limitations	1) Safety issues with reactogenicity have been reported for various RNA based vaccines 2) It also shows instability	1) The host may possess immunity against the vector due to prior exposure, reducing the efficacy. 2) May lead to cancer due to the integration of the viral genome into the host genome