Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine
A study examining the efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine (also known as the Moderna vaccine) was published in the New England Journal of Medicine on February 4th 2021.
Efficacy: This means that the efficacy of the vaccine in preventing symptomatic COVID-19 disease was 94.1% (95% CI 89.3%-96.8%; P<0.001) and was consistent in both younger (18-<65 years; vaccine efficacy= 95.6%) and older patients (>65 years; vaccine efficacy= 86.4%). Thirty patients in the trial developed severe COVID-19 disease all of whom were in the placebo group. This means that the mRNA-1273 SARS-CoV-2 vaccine was 100% effective at preventing severe COVID-19 disease.
Safety: Adverse events were more commonly reported in those who received two doses of the vaccine rather than two doses of the placebo (88.6% vs. 18.8%). The most commonly reported adverse events were injection-site reactions (mainly grade 1 or 2) and lasted for a mean of 2.6 and 3.2 days respectively. Most commonly reported systemic adverse events included headache, myalgia (muscle pain), arthralgia (bone pain), chills and fatigue and were more frequently reported after the second vaccine dose.
Summary: Overall this study shows that the efficacy of the Moderna vaccine in preventing both symptomatic COVID-19 and severe COVID-19 disease is high while the presence of adverse reactions post vaccine were limited to local injection-site reactions and some expected systemic reactions. Further studies examining the long-term duration of immunity of the Moderna vaccine are required.
Baden LR at al
N Engl J Med 2021; 384:403-416. DOI: 10.1056/NEJMoa2035389
“Single – dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCov-10(AZD1222) vaccine: a pooled analysis of four randomised trials”
A single standard dose Covid 19 AstraZeneca vaccine provided protection against primary symptomatic COVID-19 in the first 90 days with an efficacy of 76·0% (95% CI 59·3 to 85·9), there was no evidence of waning of protection in the first three months after vaccination.
Vaccine efficacy after two standard doses was 55·1% (95% CI 33·0–69·9) with an interval of less than 6 weeks and 81·3% (60·3–91·2) when more than 12 weeks apart. Higher efficacy was reported when the interval between the primary and booster dose are given more than 12 weeks apart.
Efficacy of a single standard dose against any NAAT (nucleic acid amplification test )-positive infection was 63·9% (46·0 to 75·9) from 22 days to 90 days, suggesting the potential for a substantial reduction in transmission, although these results are exploratory and require further investigation.
Merryn Voysey et al
The Lancet Published February 19, 202 DOI: https://doi.org/10.1016/S0140-6736(21)00432-3
Safety and Immunogenicity of Two RNA-Based Covid-19 Vaccine Candidates.
This study examined the safety and immunogenicity of two RNA-Based Covid-19 Vaccine candidates. The results of the study, added to earlier interim safety and immunogenicity data regarding BNT162b1 in younger adults from trials in Germany and the United States, supported the selection of *BNT162b2 for advancement to a pivotal phase 2–3 safety and efficacy evaluation .
*BNT162b2 is Comirnaty® (Pfizer/BioNTech)
Walsh E et al.
N Engl J Med 2020; 383:2439-2450 https://www.nejm.org/doi/full/10.1056/NEJMoa2027906
Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.
A total of 43,548 people aged 16 years of age or older took part in this trial.43,448 people received injections: 21,720 with BNT162b2* vaccine and 21,728 with placebo. In the group that received BNT162b2 vaccine, there were 8 cases of Covid-19 with onset at least 7 days after the second dose. In the group that received placebo, there were 162 cases of Covid-19.
A two-dose regimen of BNT162b2 resulted in95% protection against Covid-19. Safety over a median of 2 months was similar to that of other viral vaccines. Adverse events were short-term. Most common were mild-to-moderate pain at the injection site, fatigue, and headache. The incidence of serious adverse events was low and was similar in the vaccine and placebo groups.
*BNT162b2 is Comirnaty® (Pfizer/BioNTech)
Polack et al.
December 10, 2020 DOI: 10.1056/NEJMoa2034577 https://www.nejm.org/doi/full/10.1056/NEJMoa2034577
This page was updated 10 March 2021