Table 1.

COVID-19 vaccines available in the USA [22, 23]

Vaccine manufacturer	Recommended age	Schedule	General efficacy	Efficacy against the variants	Side effects		Contraindicationsa
					Local	Systemic
Pfizer-BioNTech	≥ 12 years	Two shots, 21 days apart	95% efficacy in preventing COVID-19 in those without prior infection. 100% effective at preventing severe disease	More than 95% effective against severe disease or death from the alpha variant and the beta variant. For the delta variant, 88% effective against symptomatic disease and 96% effective against hospitalization (studies not yet peer reviewed)	Pain, swelling, redness	Tiredness, headache, muscle pain, chills, fever, nausea	Severe allergic reaction (anaphylaxis) or an immediate allergic reaction
Moderna	≥ 18 years	Two shots, 28 days apart	94.1% effective at preventing symptomatic infection	May provide protection against the alpha and beta variants; awaiting confirmation from studies	Pain, redness, swelling	Tiredness, headache, muscle pain, chills, fever, nausea	Severe allergic reaction (anaphylaxis) or an immediate allergic reaction
Janssen/Johnson & Johnson	≥ 18 years	Single shot	72% overall efficacy and 86% efficacy against severe disease	Has been shown to offer protection against the alpha variant. 64% overall efficacy and 82% efficacy against severe disease in South Africa, where the beta variant was first detected. Also effective against the delta variant	Pain, redness, swelling	Tiredness, headache, muscle pain, chills, fever, nausea	Severe allergic reaction (anaphylaxis) or an immediate allergic reaction

COVID-19 coronavirus disease 2019, mRNA messenger RNA

^aIndividual with severe or immediate allergic reaction (within 4 h) that needs to be treated with epinephrine or EpiPen or with medical care after getting the first dose of an mRNA COVID-19 vaccine should not get a second dose of either of the mRNA COVID-19 vaccines