(STUDY) Higher risk of adverse events for mRNA Covid-19 vaccines


A study in the journal Vaccine finds: Excess risk of serious adverse events from Pfizer and Moderna Covid-19 vaccines outweighs risks from Covid-19 itself.

Pfizer vaccine: 36% higher risk of serious adverse events than placebo. Moderna: 6% higher. Combined: 16% higher.

The following is an excerpt from the journal article published in Vaccine: “Serious Adverse Events of Special Interest following mRNA Covid-19 Vaccination in Randomized Trials in Adults.”

Introduction

In 2020, prior to COVID-19 vaccine rollout, the Brighton Collaboration created a priority list, endorsed by the World Health Organization, of potential adverse events relevant to COVID-19 vaccines. We adapted the Brighton Collaboration list to evaluate serious adverse events of special interest observed in mRNA COVID-19 vaccine trials.

Methods

Secondary analysis of serious adverse events reported in the placebo-controlled, phase III randomized clinical trials of Pfizer and Moderna mRNA Covid-19 vaccines in adults (NCT04368728 and NCT04470427), focusing analysis on Brighton Collaboration adverse events of special interest.

Results

Pfizer and Moderna mRNA Covid-19 vaccines were associated with an excess risk of serious adverse events of special interest of 10.1 and 15.1 per 10,000 vaccinated over placebo baselines of 17.6 and 42.2 (95 % CI −0.4 to 20.6 and −3.6 to 33.8), respectively.

The Pfizer trial exhibited a 36 % higher risk of serious adverse events in the vaccine group; risk difference 18.0 per 10,000 vaccinated (95 % CI 1.2 to 34.9); risk ratio 1.36 (95 % CI 1.02 to 1.83).

The Moderna trial exhibited a 6 % higher risk of serious adverse events in the vaccine group: risk difference 7.1 per 10,000 (95 % CI –23.2 to 37.4); risk ratio 1.06 (95 % CI 0.84 to 1.33). 

Combined, there was a 16 % higher risk of serious adverse events in mRNA vaccine recipients: risk difference 13.2 (95 % CI −3.2 to 29.6); risk ratio 1.16 (95 % CI 0.97 to 1.39).

Discussion

The excess risk of serious adverse events found in our study points to the need for formal harm-benefit analyses, particularly those that are stratified according to risk of serious Covid-19 outcomes.

These analyses will require public release of participant level datasets.

Read full abstract and view data sets here.


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3 thoughts on “(STUDY) Higher risk of adverse events for mRNA Covid-19 vaccines”

  1. What kind of adverse effects/events? Suddenly, my knees started with rheumatoid arthritis. This does not run in my family. Has this happened to anyone else?

    1. Various vaccines are well established to cause inflammation and arthritis. Looking at Covid vaccine adverse event reports, there are many reports of arthritis. Causality isn’t necessarily accepted.

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