Table 2.

Summary table of mRNA vaccines safety and efficacy.

Name of the vaccine	NT162b2	mRNA-1273
Company developer	Pfizer/BioNTech	Moderna
Type	mRNA	mRNA
Doses and suggested interval	2 doses 3 weeks apart Booster dose 6 months following primary series for the following: Adults 65 years or older Adults 18 years or older at high risk for severe COVID-19 because of comorbidities Adults 18 years or older at occupational or institutional risk of exposure	2 doses 4 weeks apart
Efficacy against symptomatic COVID-19 (in clinical trials)	95 % (95 % CI 90–98) after a median of 2 months follow-up 91 % (95 % CI 89–93) after median of 6 months follow-up	94 % (95 % CI 89–97) after median of 2 months follow-up
Effectiveness in observational studies when Delta variant prevalent	Symptomatic infection: 41 to 88 % Severe disease/ hospitalization: 86 to 95 %	Symptomatic infection: 85 to 88 % Severe disease/ hospitalization: 89 to 96 %
Storage requirements	Ultracold freezer (–90 to –60 °C) then freezer (–25 to –15 °C) for up to 2 weeks cumulative time then refrigerated (2 to 8 °C) for up to 1 month	Freezer (–25 to –15 °C) then refrigerated (2 to 8 °C) for up to 30 days
Common side effects	Local injection site reactions Systemic symptoms (fevers, chills, fatigue, myalgias, headache)	Local injection site reactions Systemic symptoms (fevers, chills, fatigue, myalgias, headache)
Rare adverse effects	Anaphylaxis (approximately 5 per million) Myocarditis/pericarditis (approximately 16 per million among 16–39-year-olds)	Anaphylaxis (approximately 2.8 per million) Myocarditis/pericarditis (approximately 16 per million among 16–39-year-olds)