An overwhelming majority of the reactions were mild, such as headaches and fatigue.
In clinical trials, the Pfizer and Modern COVID-19 vaccines showed low doses of serious side effects. The actual data from the first month of vaccine administration in the US confirms this.
A new report from the CDC looks at the numbers of VAERS, a portal monitored by the government, and where health workers in the US should report adverse events after vaccinations.
In a month in which nearly 14 million doses of vaccine were administered, only about 7,000 reports were sent to VAERS, of which 91% described mild incidents such as headaches, fatigue, and dizziness.
Anaphylaxis, a vaccine response that received wide media coverage, was found to be unusual: 62 total cases were reported at a dose of 4.5 per million doses – comparable to the rate of anaphylaxis with other common vaccines.
Amid the 14 million doses, 113 deaths were reported to VAERS; 78 of long-term care facilities and 35 outside the facilities – and so far none of the deaths have been directly linked to the vaccine.
The data is not entirely surprising, says William Schaffner, MD, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center.
“The comprehensiveness of the safety evaluation was better than what we did for any licensed vaccine we used in the United States,” he told ABC News. “The clinical trials of both vaccinations were very extensive, and both showed very low severity of adverse reactions.”
The CDC also collected patient-reported data from v-safe, a smartphone app for reporting voluntary side effects. Of the 1.6 million vaccine recipients who participated, the majority reported mild side effects such as injection site pain, fatigue, headache, and chills. These symptoms were allegedly most prominent in the first day after injection – and worse with the second dose – but improved each subsequent day and disappeared by day 3 or 4.
The app has also collected data on pregnancy status, and the nearly 11,000 women who reported being pregnant will be tracked in a dedicated registry.
The CDC’s data is limited because it relies heavily on self-reported data. For example, in both the VAERS and v-safe reports, the most adverse events were observed in women. But as Schaffner describes, this does not necessarily mean that women are more prone to reactions.
“I am more likely to believe that reporting is a bias,” he said, describing the well-documented difference in health care use between men and women. “Women are more likely to seek medical attention and more likely to report illness.”
Those who judge the rate of explosion of the vaccine as too hasty can rest assured by the CDC reporting, Schaffner says.
“Now that we have very well analyzed data from a very comprehensive range of surveillance systems, we can go beyond the very large studies and say, ‘Look, we’re doing this in the real world, among your friends and neighbors,” he said. said. “This vaccine remains very, very safe.”
Eric Silberman, MD, a family physician in internal medicine at Northwestern Memorial Hospital, is contributing to the ABC News Medical Unit.