tetano
Editor, Senior Moderator
Open Forum Infect Dis
. 2022 Aug 22;9(9)
fac408.
doi: 10.1093/ofid/ofac408. eCollection 2022 Sep.
Efficacy of Approved Versus Unapproved Vaccines for Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Randomized Blinded Clinical Trials
Andrea Perez Navarro[SUP] 1 [/SUP], Victoria Pilkington[SUP] 2 [/SUP], Toby Pepperrell[SUP] 3 [/SUP], Manya Mirchandani[SUP] 1 [/SUP], Jacob Levi[SUP] 4 [/SUP], Andrew Hill[SUP] 5 [/SUP]
Affiliations
Abstract
Background: Five severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are approved in North America and/or Europe: Pfizer/BioNTech, Moderna, Janssen, Oxford-AstraZeneca, and Novavax. Other vaccines have been developed, including Sinopharm, SinoVac, QazVac, Covaxin, Soberana, Zifivax, Medicago, Clover, and Cansino, but they are not approved in high-income countries. This meta-analysis compared the efficacy of US Food and Drug Administration (FDA)/European Medicines Agency (EMA)-approved and -unapproved vaccines in randomized clinical trials (RCTs).
Methods: A systematic review of trial registries identified RCTs of SARS-CoV-2 vaccines. Risk of bias was assessed using the Cochrane tool (RoB 2). In the meta-analysis, relative risks of symptomatic infection and severe disease were compared for each vaccine versus placebo, using Cochrane-Mantel Haenszel Tests (random effects method).
Results: Twenty-two RCTs were identified and 1 was excluded for high-risk of bias. Ten RCTs evaluated 5 approved vaccines and 11 RCTs evaluated 9 unapproved vaccines. In the meta-analysis, prevention of symptomatic infection was 84% (95% confidence interval [CI], 68%-92%) for approved vaccines versus 72% (95% CI, 66%-77%) for unapproved vaccines, with no significant difference between vaccine types (P = .12). Prevention of severe SARS-CoV-2 infection was 94% (95% CI, 75%-98%) for approved vaccines versus 86% (95% CI, 76%-92%) for unapproved vaccines (P = .33). The risk of serious adverse events was similar between vaccine types (P = .12).
Conclusions: This meta-analysis of 21 RCTs in 390 459 participants showed no significant difference in efficacy between the FDA/EMA-approved and -unapproved vaccines for symptomatic or severe infection. Differences in study design, endpoint definitions, variants, and infection prevalence may have influenced results. New patent-free vaccines could lower costs of worldwide SARS-CoV-2 vaccination campaigns significantly.
Keywords: COVID-19 vaccination; access to medicines; vaccines.
. 2022 Aug 22;9(9)
fac408.doi: 10.1093/ofid/ofac408. eCollection 2022 Sep.
Efficacy of Approved Versus Unapproved Vaccines for Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Randomized Blinded Clinical Trials
Andrea Perez Navarro[SUP] 1 [/SUP], Victoria Pilkington[SUP] 2 [/SUP], Toby Pepperrell[SUP] 3 [/SUP], Manya Mirchandani[SUP] 1 [/SUP], Jacob Levi[SUP] 4 [/SUP], Andrew Hill[SUP] 5 [/SUP]
Affiliations
- PMID: 36092832
- PMCID: PMC9452066
- DOI: 10.1093/ofid/ofac408
Abstract
Background: Five severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are approved in North America and/or Europe: Pfizer/BioNTech, Moderna, Janssen, Oxford-AstraZeneca, and Novavax. Other vaccines have been developed, including Sinopharm, SinoVac, QazVac, Covaxin, Soberana, Zifivax, Medicago, Clover, and Cansino, but they are not approved in high-income countries. This meta-analysis compared the efficacy of US Food and Drug Administration (FDA)/European Medicines Agency (EMA)-approved and -unapproved vaccines in randomized clinical trials (RCTs).
Methods: A systematic review of trial registries identified RCTs of SARS-CoV-2 vaccines. Risk of bias was assessed using the Cochrane tool (RoB 2). In the meta-analysis, relative risks of symptomatic infection and severe disease were compared for each vaccine versus placebo, using Cochrane-Mantel Haenszel Tests (random effects method).
Results: Twenty-two RCTs were identified and 1 was excluded for high-risk of bias. Ten RCTs evaluated 5 approved vaccines and 11 RCTs evaluated 9 unapproved vaccines. In the meta-analysis, prevention of symptomatic infection was 84% (95% confidence interval [CI], 68%-92%) for approved vaccines versus 72% (95% CI, 66%-77%) for unapproved vaccines, with no significant difference between vaccine types (P = .12). Prevention of severe SARS-CoV-2 infection was 94% (95% CI, 75%-98%) for approved vaccines versus 86% (95% CI, 76%-92%) for unapproved vaccines (P = .33). The risk of serious adverse events was similar between vaccine types (P = .12).
Conclusions: This meta-analysis of 21 RCTs in 390 459 participants showed no significant difference in efficacy between the FDA/EMA-approved and -unapproved vaccines for symptomatic or severe infection. Differences in study design, endpoint definitions, variants, and infection prevalence may have influenced results. New patent-free vaccines could lower costs of worldwide SARS-CoV-2 vaccination campaigns significantly.
Keywords: COVID-19 vaccination; access to medicines; vaccines.