COVID vaccines not linked to excess deaths, says CDC
There is no evidence that vaccination with either the Pfizer/BioNTech or Moderna's mRNA-based COVID-19 vaccines led to the death of patients, says a study by researchers at the Centres for Disease Control and Prevention (CDC).
The analysis of data from US adverse event monitoring systems comes from the first six months after vaccination with the two vaccine started in the US, a period in which just under 4,500 people died after being vaccinated and almost 300 million doses were administered in the US.
"We found no unusual patterns in cause of death among the death reports received," write the scientists in a paper published in The Lancet medical journal.
In fact, 92% of side effects associated with use of Pfizer/BioNTech's Comirnaty and Moderna's Spikevax were mild and short-lived, mainly local injection site reactions, fatigue and headache in the first week after dosing. All the cases recorded in the dataset were in people aged 16 or over.
Less than 1% of participants reported seeking medical care after vaccination, according to the data, which came from the well established Vaccine Adverse Event Reporting System (VAERS) as well as v-safe, a voluntary smartphone-based system introduced in 2020 specifically to monitor COVID-19 vaccine safety.
The VAERS data included 340,000 reports, of which 22,000 were recorded as serious – including shortness of breath, elevated temperature and headache – and just under 4,500 were deaths.
There were nearly 8 million v-safe reports, with the most frequently reported events injection-site pain, fatigue, and headache, but less than 1% of those prompted the patient to seek medical care.
The researchers note that the timing of the assessment meant that the sample included a lot of older people in the 65 and over age bracket, who were more vulnerable to COVID-19 and so were offered vaccination earlier.
Because COVID-19 vaccines have been authorised under emergency use, healthcare providers are required to report all deaths following vaccination, regardless of the potential direct association.
The deaths recorded in the first few days after vaccination with the mRNA vaccines were no more frequent than is seen with other adult vaccinations, and followed a similar pattern, according to the team.
Other findings were that females and individuals aged 65 and younger reported more reactogenicity following vaccination than males and older adults.
There are limitations to the study, including that the VAERS is a passive system and generally can't establish causal relationships between vaccination and adverse events, while v-safe may be under-reporting side effects in in socioeconomically disadvantaged populations with less access to digital devices.
Nevertheless, study co-author Hannah Rosenblum said that "COVID-19 vaccine safety monitoring is the most robust in US history and the two complementary surveillance systems used in this study should bolster confidence that mRNA COVID-19 vaccines are safe."
Commenting on the study in a related Lancet editorial, Elizabeth Phillips of Vanderbilt University Medical Center in the US, said while around one in 1,000 people have an adverse effect with vaccination, most are non-serious.
"For adverse events of special interest, it is reassuring that there were no unexpected signals other than myopericarditis and anaphylaxis, already known to be associated with mRNA vaccines," she added.
