It’s not a stop-show, but the number of allergic reactions to Pfizer’s COVID-19 vaccine has certainly started to raise eyebrows – epidemiologically, anyway. The leading scientist in Operation Warp Speed said the frequency of allergic reactions is still incredibly low, but it has slipped more than might be expected from other vaccines. Pfizer may need more studies among people at higher risk for allergies, Dr. Moncef Slaoui suggested:
The frequency of allergic reactions to the Pfizer Covid-19 vaccine is higher than would be expected for other vaccines, Dr. Moncef Slaoui, chief scientific adviser for Operation Warp Speed, said on Wednesday. …
“This frequency, as it was yesterday, is higher than what could be expected with other vaccines,” he said.
Slaoui said there are discussions between vaccine manufacturers and the National Institutes of Health to consider conducting clinical trials of Covid-19 vaccines in highly allergic populations, such as those who need to carry an EpiPen with them at all times.
What exactly does it mean that the frequency is “higher”? How many serious reactions have been reported? As of Tuesday, Slaoui told CNN, the number remained at … six. But six of how many?
Over a million and counting, what leads the world:
The United States now leads the world in Covid-19 vaccines, with 1,008,025 doses administered within 10 days of the first doses being eliminated for use, according to the Centers for Disease Control and Prevention.
State-run vaccination campaigns launch photos from Pfizer Inc. and Moderna Inc., initially focused on hundreds of thousands of health care workers across the country who fought the virus on the front lines of hospitals. Vaccines require two fires a week away to provide the highest level of protection.
China, which has several vaccines grown at home, has vaccinated more than 650,000 people and says it has administered 1 million doses. This figure could actually be much higher or at least higher than the US total, as the country has provided rare updates on its efforts. Russia has vaccinated 440,000 people. Both countries received an advance in August by authorizing domestically produced vaccines before they were fully tested.
Six out of a million? This is a fairly low frequency rate, which is why it did not appear in the phase 3 studies. This population would have been around 30,000 people in the active group; If it had even produced an unexpected allergic reaction, we would have seen dozens or dozens of serious allergic reactions so far. This is why the CDC and the FDA have granted emergency use authorization only to Pfizer and Moderna; will require more studies to address the remaining questions about the impact on certain subpopulations, especially as they arise during EUA vaccinations.
However, this is not a reason to stop now. Compare the frequency of allergic response observed so far with the lethality rate of the virus. At the lowest estimate of 0.4% lethality (the flu is generally about 0.1%), you would expect to see 4,000 deaths in a population of one million infections. Six serious allergic reactions simply do not compare on the basis of risk. An allergic reaction can be fatal, but the numbers clearly show that it is still an extremely rare event, and the shot is a much better game than staying unvaccinated.
Finally, some complain that the US will miss its target of 20 million vaccinations by the end of the month. This has always been a bit aspirational, and the logistics turn out to be complicated – as everyone should have known it would be. Getting a million vaccinations in the first ten days is still an amazing pace, and I just added the second vaccine from Moderna three days ago. Once states eliminate logistics and priority rankings, the pace should increase considerably. If it takes us until January 10 or so to reach 20 million, this is still an amazing achievement.