Global COVID Vaccine Safety study identified already-known risks, doesn’t show that risks are greater than benefits

Key takeaway

No medical intervention, including vaccines, is entirely free of risk. While COVID-19 vaccines are associated with a risk of certain health problems, including myocarditis and a particular type of blood clot, COVID-19 is associated with a much greater risk of developing cardiovascular, neurological, and hematological disorders compared to the vaccines. Getting vaccinated reduces the risk of severe disease and death. The benefits of COVID-19 vaccines outweigh their risks.

Reviewed content

Verdict:

Inaccurate

Claim:

Global COVID Vaccine Safety study shows that COVID-19 vaccines are dangerous, inadequately tested; getting vaccinated is more dangerous than getting COVID-19

Verdict detail

Factually inaccurate: Multiple studies have found that COVID-19 vaccines are associated with a lower risk of various health problems, including cardiovascular, neurological, and hematological disorders, compared to COVID-19 itself.
Misrepresents source: Most of the safety signals identified in the study had been known to us since 2021. These include myocarditis following mRNA vaccination and cerebral venous sinus thrombosis following viral vector vaccination. The study didn’t find that the risks of the COVID-19 vaccines outweighed their benefits.

See our method of evaluation

Full Claim

Global COVID Vaccine Safety study findings are “horrifying”; COVID-19 vaccines were “rushed, sloppily tested”; the risks of COVID-19 vaccination are greater than that of COVID-19

In late February 2024, a flurry of posts appeared on social media platforms like Instagram, revolving around a study newly published in the scientific journal Vaccine. This is part of the Global COVID Vaccine Safety project that analyzed adverse events following vaccination^[1].

Many of these posts cited the study to promote claims that COVID-19 vaccines were dangerous, or that they weren’t adequately tested, or that the vaccines posed greater risks than COVID-19 itself. The headlines of several articles, such as this one by the Gateway Pundit and another by RT (formerly Russia Today), also simply described the study as having found health problems linked to COVID-19 vaccines with no preamble.

None of these claims are anything new—we’ve seen them crop up repeatedly during the COVID-19 pandemic, each time latching onto inaccurate, misleading interpretations of various data and scientific studies.

As we will explain below, such portrayals of the study aimed at advancing anti-vaccine narratives misrepresent its findings.

What did the study do and what did it find?

The study is part of a continuing, collaborative effort by the Global Vaccine Data Network (GVDN) to evaluate COVID-19 vaccine safety. GVDN is described as “a multinational collaboration ready to conduct globally coordinated epidemiological studies on the safety and effectiveness of vaccines, including COVID-19 vaccines”.

One of the study’s main advantages is its very large sample size, which includes more than 99 million people from eight countries. This enables the study to identify very rare vaccine adverse events that might not otherwise be detected using data from a single country or region. In addition, collaboration across multiple countries enables the project to standardize approaches and more quickly evaluate vaccine safety concerns.

The adverse events selected for analysis were a set of conditions known to be associated with vaccination in general. Adverse events from 14 COVID-19 vaccines were evaluated. These included the most widely known ones, like the Pfizer-BioNTech and Moderna mRNA vaccines, the Janssen vaccine, and Novavax, but also those like Sinovac and Sputnik. The risk for adverse events was evaluated at different periods after vaccination, for up to 42 days.

Most of the safety signals identified in the study have been known to us since 2021. Specifically, the study identified an association between myocarditis and pericarditis after mRNA vaccines, and Guillain-Barré syndrome and cerebral venous sinus thrombosis (a type of blood clot in the brain) after viral vector vaccines.

Additionally, the study also identified other potential safety signals, such as for acute disseminated encephalomyelitis (ADEM; inflammation and swelling in the brain and spinal cord) after viral vector and mRNA vaccines. But the authors added that this required more follow-up studies to confirm, as these events didn’t follow a consistent pattern or timing after vaccination and the number of ADEM events detected was very, very small (seven observed cases from 10.5 million doses administered).

The study contains some limitations. For instance, differences in healthcare infrastructure and surveillance systems, which “can introduce bias and affect the comparability of results”. Additionally, the background rates used to compare the rate of adverse events post-vaccination didn’t account for factors like pre-existing medical conditions.

Study findings confirm what we already know about COVID-19 vaccine risks, don’t show that risks outweigh the benefits

Some posts implied that the study found novel risks associated with the COVID-19 vaccines. As we have already noted above, this isn’t true. Most of the adverse reactions detected in the study had already been recognized in 2021 and acknowledged by authorities^[2-7].

We reached out to one of the study’s authors, Helen Petousis-Harris, co-director for the GVDN and associate professor at the University of Auckland.

In an email, Petousis-Harris explained that their “findings are consistent with previous knowledge but do add more detail thanks to the size and diversity of the population observed”. She cautioned that “[t]his type of study does not inform us about risk or causality, it is used for the detection of potential safety signals that should be followed up”.

Therefore, the implication in some social media posts that the risks reported in the study were a revelation or had gone unacknowledged by authorities is inaccurate.

Petousis-Harris also refuted claims that the study showed the risks of COVID-19 vaccines outweighed their benefits.

“No vaccine is 100% without risk but the risks from COVID-19 vaccines are extremely low. Risks from the infection are much higher,” she said.

Indeed, while COVID-19 mRNA vaccines are associated with a slightly elevated risk of myocarditis and viral vector vaccines with a particular type of blood clot, studies have found that the risk of heart complications and blood clots associated with COVID-19 is greater^[7-9].

She also countered the claim that the study presented “horrifying” findings. “The findings are reassuring,” she said, as “this huge study did not reveal anything unexpected that had not been raised before […] and shows that these adverse events are very rare”.

Claims that COVID-19 vaccines were inadequately tested or experimental are nothing new. Health Feedback addressed the claims in several earlier reviews. The narrative is that the COVID-19 vaccines must have been rushed to market, since other vaccines took several years to complete testing and obtain approval, whereas the COVID-19 vaccines took only two years.

But as this article by the British Society for Immunology explains, the speed with which this was accomplished mainly had to do with the urgency needed to tackle the COVID-19 pandemic. This meant that unlike other vaccines, there were an unprecedented amount of resources dedicated specifically towards the vaccine manufacturing process and review of the scientific data for COVID-19 vaccines. Additionally, more funding was put towards the development of the COVID-19 vaccines.

The concerted, collaborative effort to accelerate the vaccine development timeline enabled COVID-19 vaccines to be developed, tested, and authorized more quickly than other vaccines. COVID-19 vaccines reached the market quicker than other vaccines not because corners were cut, but because it was the number one priority on everyone’s agenda, from governments to regulatory agencies to the scientific community.

REFERENCES

• 1 – Faktova et al. (2024) COVID-19 vaccines and adverse events of special interest: A multinational Global Vaccine Data Network (GVDN) cohort study of 99 million vaccinated individuals. Vaccine.
• 2 – Mevorach et al. (2021) Myocarditis after BNT162b2 mRNA Vaccine against Covid-19 in Israel. New England Journal of Medicine.
• 3 – Simone et al. (2021) Acute Myocarditis Following COVID-19 mRNA Vaccination in Adults Aged 18 Years or Older. JAMA Internal Medicine.
• 4 – Witberg et al. (2021) Myocarditis after Covid-19 Vaccination in a Large Health Care Organization. New England Journal of Medicine.
• 5 – Montgomery et al. (2021) Myocarditis Following Immunization With mRNA COVID-19 Vaccines in Members of the US Military. JAMA Cardiology.
• 6 – See et al. (2021) US Case Reports of Cerebral Venous Sinus Thrombosis With Thrombocytopenia After Ad26.COV2.S Vaccination, March 2 to April 21, 2021. JAMA.
• 7 – Hippisley-Cox et al. (2021) Risk of thrombocytopenia and thromboembolism after covid-19 vaccination and SARS-CoV-2 positive testing: self-controlled case series study. BMJ.
• 8 – Knight et al. (2022) Association of COVID-19 With Major Arterial and Venous Thrombotic Diseases: A Population-Wide Cohort Study of 48 Million Adults in England and Wales. Circulation.
• 9 – Barda et al. (2021) Safety of the BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Setting. New England Journal of Medicine.