On this blog, we have some people who continue to promote conspiracy theories about Covid and Covid vaccinations. It is, therefore, time, I feel, to present them with some solid evidence on the subject (even though it means departing from our usual focus on SCAM).
This Cochrane review assessed the efficacy and safety of COVID‐19 vaccines (as a full primary vaccination series or a booster dose) against SARS‐CoV‐2. An impressive team of investigators searched the Cochrane COVID‐19 Study Register and the COVID‐19 L·OVE platform (last search date 5 November 2021). They also searched the WHO International Clinical Trials Registry Platform, regulatory agency websites, and Retraction Watch. They included randomized controlled trials (RCTs) comparing COVID‐19 vaccines to placebo, no vaccine, other active vaccines, or other vaccine schedules.
A total of 41 RCTs could be included and analyzed assessing 12 different vaccines, including homologous and heterologous vaccine schedules and the effect of booster doses. Thirty‐two RCTs were multicentre and five were multinational. The sample sizes of RCTs were 60 to 44,325 participants. Participants were aged: 18 years or older in 36 RCTs; 12 years or older in one RCT; 12 to 17 years in two RCTs; and three to 17 years in two RCTs. Twenty‐nine RCTs provided results for individuals aged over 60 years, and three RCTs included immunocompromised patients. No trials included pregnant women. Sixteen RCTs had two‐month follow-ups or less, 20 RCTs had two to six months, and five RCTs had greater than six to 12 months or less. Eighteen reports were based on preplanned interim analyses. The overall risk of bias was low for all outcomes in eight RCTs, while 33 had concerns for at least one outcome. 343 registered RCTs with results not yet available were identified.The evidence for mortality was generally sparse and of low or very low certainty for all WHO‐approved vaccines, except AD26.COV2.S (Janssen), which probably reduces the risk of all‐cause mortality (risk ratio (RR) 0.25, 95% CI 0.09 to 0.67; 1 RCT, 43,783 participants; high‐certainty evidence).High‐certainty evidence was found that BNT162b2 (BioNtech/Fosun Pharma/Pfizer), mRNA‐1273 (ModernaTx), ChAdOx1 (Oxford/AstraZeneca), Ad26.COV2.S, BBIBP‐CorV (Sinopharm‐Beijing), and BBV152 (Bharat Biotect) reduce the incidence of symptomatic COVID‐19 compared to placebo (vaccine efficacy (VE): BNT162b2: 97.84%, 95% CI 44.25% to 99.92%; 2 RCTs, 44,077 participants; mRNA‐1273: 93.20%, 95% CI 91.06% to 94.83%; 2 RCTs, 31,632 participants; ChAdOx1: 70.23%, 95% CI 62.10% to 76.62%; 2 RCTs, 43,390 participants; Ad26.COV2.S: 66.90%, 95% CI 59.10% to 73.40%; 1 RCT, 39,058 participants; BBIBP‐CorV: 78.10%, 95% CI 64.80% to 86.30%; 1 RCT, 25,463 participants; BBV152: 77.80%, 95% CI 65.20% to 86.40%; 1 RCT, 16,973 participants).Moderate‐certainty evidence was found that NVX‐CoV2373 (Novavax) probably reduces the incidence of symptomatic COVID‐19 compared to placebo (VE 82.91%, 95% CI 50.49% to 94.10%; 3 RCTs, 42,175 participants).There is low‐certainty evidence for CoronaVac (Sinovac) for this outcome (VE 69.81%, 95% CI 12.27% to 89.61%; 2 RCTs, 19,852 participants).High‐certainty evidence was found that BNT162b2, mRNA‐1273, Ad26.COV2.S, and BBV152 result in a large reduction in the incidence of severe or critical disease due to COVID‐19 compared to placebo (VE: BNT162b2: 95.70%, 95% CI 73.90% to 99.90%; 1 RCT, 46,077 participants; mRNA‐1273: 98.20%, 95% CI 92.80% to 99.60%; 1 RCT, 28,451 participants; AD26.COV2.S: 76.30%, 95% CI 57.90% to 87.50%; 1 RCT, 39,058 participants; BBV152: 93.40%, 95% CI 57.10% to 99.80%; 1 RCT, 16,976 participants).
Moderate‐certainty evidence was found that NVX‐CoV2373 probably reduces the incidence of severe or critical COVID‐19 (VE 100.00%, 95% CI 86.99% to 100.00%; 1 RCT, 25,452 participants).
Two trials reported high efficacy of CoronaVac for severe or critical disease with wide CIs, but these results could not be pooled.
mRNA‐1273, ChAdOx1 (Oxford‐AstraZeneca)/SII‐ChAdOx1 (Serum Institute of India), Ad26.COV2.S, and BBV152 probably result in little or no difference in serious adverse events (SAEs) compared to placebo (RR: mRNA‐1273: 0.92, 95% CI 0.78 to 1.08; 2 RCTs, 34,072 participants; ChAdOx1/SII‐ChAdOx1: 0.88, 95% CI 0.72 to 1.07; 7 RCTs, 58,182 participants; Ad26.COV2.S: 0.92, 95% CI 0.69 to 1.22; 1 RCT, 43,783 participants); BBV152: 0.65, 95% CI 0.43 to 0.97; 1 RCT, 25,928 participants). In each of these, the likely absolute difference in effects was fewer than 5/1000 participants.
Evidence for SAEs is uncertain for BNT162b2, CoronaVac, BBIBP‐CorV, and NVX‐CoV2373 compared to placebo (RR: BNT162b2: 1.30, 95% CI 0.55 to 3.07; 2 RCTs, 46,107 participants; CoronaVac: 0.97, 95% CI 0.62 to 1.51; 4 RCTs, 23,139 participants; BBIBP‐CorV: 0.76, 95% CI 0.54 to 1.06; 1 RCT, 26,924 participants; NVX‐CoV2373: 0.92, 95% CI 0.74 to 1.14; 4 RCTs, 38,802 participants).
The authors’ conclusions were as follows: Compared to placebo, most vaccines reduce, or likely reduce, the proportion of participants with confirmed symptomatic COVID‐19, and for some, there is high‐certainty evidence that they reduce severe or critical disease. There is probably little or no difference between most vaccines and placebo for serious adverse events. Over 300 registered RCTs are evaluating the efficacy of COVID‐19 vaccines, and this review is updated regularly on the COVID‐NMA platform (covid-nma.com).
As some conspiratorial loons will undoubtedly claim that this review is deeply biased; it might be relevant to add the conflicts of interest of its authors:
- Carolina Graña: none known.
- Lina Ghosn: none known.
- Theodoros Evrenoglou: none known.
- Alexander Jarde: none known.
- Silvia Minozzi: no relevant interests; Joint Co‐ordinating Editor and Method editor of the Drugs and Alcohol Group.
- Hanna Bergman: Cochrane Response – consultant; WHO – grant/contract (Cochrane Response was commissioned by the WHO to perform review tasks that contribute to this publication).
- Brian Buckley: none known.
- Katrin Probyn: Cochrane Response – consultant; WHO – consultant (Cochrane Response was commissioned to perform review tasks that contribute to this publication).
- Gemma Villanueva: Cochrane Response – employment (Cochrane Response has been commissioned by WHO to perform parts of this systematic review).
- Nicholas Henschke: Cochrane Response – consultant; WHO – consultant (Cochrane Response was commissioned by the WHO to perform review tasks that contributed to this publication).
- Hillary Bonnet: none known.
- Rouba Assi: none known.
- Sonia Menon: P95 – consultant.
- Melanie Marti: no relevant interests; Medical Officer at WHO.
- Declan Devane: Health Research Board (HRB) – grant/contract; registered nurse and registered midwife but no longer in clinical practice; Editor, Cochrane Pregnancy and Childbirth Group.
- Patrick Mallon: AstraZeneca – Advisory Board; spoken of vaccine effectiveness to media (print, online, and live); works as a consultant in a hospital that provides vaccinations; employed by St Vincent’s University Hospital.
- Jean‐Daniel Lelievre: no relevant interests; published numerous interviews in the national press on the subject of COVID vaccination; Head of the Department of Infectious Diseases and Clinical Immunology CHU Henri Mondor APHP, Créteil; WHO (IVRI‐AC): expert Vaccelarate (European project on COVID19 Vaccine): head of WP; involved with COVICOMPARE P et M Studies (APHP, INSERM) (public fundings).
- Lisa Askie: no relevant interests; Co‐convenor, Cochrane Prospective Meta‐analysis Methods Group.
- Tamara Kredo: no relevant interests; Medical Officer in an Infectious Diseases Clinic at Tygerberg Hospital, Stellenbosch University.
- Gabriel Ferrand: none known.
- Mauricia Davidson: none known.
- Carolina Riveros: no relevant interests; works as an epidemiologist.
- David Tovey: no relevant interests; Emeritus Editor in Chief, Feedback Editors for 2 Cochrane review groups.
- Joerg J Meerpohl: no relevant interests; member of the German Standing Vaccination Committee (STIKO).
- Giacomo Grasselli: Pfizer – speaking engagement.
- Gabriel Rada: none known.
- Asbjørn Hróbjartsson: no relevant interests; Cochrane Methodology Review Group Editor.
- Philippe Ravaud: no relevant interests; involved with Mariette CORIMUNO‐19 Collaborative 2021, the Ministry of Health, Programme Hospitalier de Recherche Clinique, Foundation for Medical Research, and AP‐HP Foundation.
- Anna Chaimani: none known.
- Isabelle Boutron: no relevant interests; member of Cochrane Editorial Board.
And as some might say this analysis is not new, here are two further papers just out:
Objectives To determine the association between covid-19 vaccination types and doses with adverse outcomes of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection during the periods of delta (B.1.617.2) and omicron (B.1.1.529) variant predominance.
Design Retrospective cohort.
Setting US Veterans Affairs healthcare system.
Participants Adults (≥18 years) who are affiliated to Veterans Affairs with a first documented SARS-CoV-2 infection during the periods of delta (1 July-30 November 2021) or omicron (1 January-30 June 2022) variant predominance. The combined cohorts had a mean age of 59.4 (standard deviation 16.3) and 87% were male.
Interventions Covid-19 vaccination with mRNA vaccines (BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna)) and adenovirus vector vaccine (Ad26.COV2.S (Janssen/Johnson & Johnson)).
Main outcome measures Stay in hospital, intensive care unit admission, use of ventilation, and mortality measured 30 days after a positive test result for SARS-CoV-2.
Results In the delta period, 95 336 patients had infections with 47.6% having at least one vaccine dose, compared with 184 653 patients in the omicron period, with 72.6% vaccinated. After adjustment for patient demographic and clinical characteristics, in the delta period, two doses of the mRNA vaccines were associated with lower odds of hospital admission (adjusted odds ratio 0.41 (95% confidence interval 0.39 to 0.43)), intensive care unit admission (0.33 (0.31 to 0.36)), ventilation (0.27 (0.24 to 0.30)), and death (0.21 (0.19 to 0.23)), compared with no vaccination. In the omicron period, receipt of two mRNA doses were associated with lower odds of hospital admission (0.60 (0.57 to 0.63)), intensive care unit admission (0.57 (0.53 to 0.62)), ventilation (0.59 (0.51 to 0.67)), and death (0.43 (0.39 to 0.48)). Additionally, a third mRNA dose was associated with lower odds of all outcomes compared with two doses: hospital admission (0.65 (0.63 to 0.69)), intensive care unit admission (0.65 (0.59 to 0.70)), ventilation (0.70 (0.61 to 0.80)), and death (0.51 (0.46 to 0.57)). The Ad26.COV2.S vaccination was associated with better outcomes relative to no vaccination, but higher odds of hospital stay and intensive care unit admission than with two mRNA doses. BNT162b2 was generally associated with worse outcomes than mRNA-1273 (adjusted odds ratios between 0.97 and 1.42).
Conclusions In veterans with recent healthcare use and high occurrence of multimorbidity, vaccination was robustly associated with lower odds of 30 day morbidity and mortality compared with no vaccination among patients infected with covid-19. The vaccination type and number of doses had a significant association with outcomes.
SECOND EXAMPLE Long COVID, or complications arising from COVID-19 weeks after infection, has become a central concern for public health experts. The United States National Institutes of Health founded the RECOVER initiative to better understand long COVID. We used electronic health records available through the National COVID Cohort Collaborative to characterize the association between SARS-CoV-2 vaccination and long COVID diagnosis. Among patients with a COVID-19 infection between August 1, 2021 and January 31, 2022, we defined two cohorts using distinct definitions of long COVID—a clinical diagnosis (n = 47,404) or a previously described computational phenotype (n = 198,514)—to compare unvaccinated individuals to those with a complete vaccine series prior to infection. Evidence of long COVID was monitored through June or July of 2022, depending on patients’ data availability. We found that vaccination was consistently associated with lower odds and rates of long COVID clinical diagnosis and high-confidence computationally derived diagnosis after adjusting for sex, demographics, and medical history.
There are, of course, many more articles on the subject for anyone keen to see the evidence. Sadly, I have little hope that the COVID loons will be convinced by any of them. Yet, I thought I should give it nevertheless a try.