It’s not an obstacle, but the number of allergic reactions to Pfizer’s COVID-19 vaccine has definitely started to raise eyebrows – epidemiologically, at least. Operation Warp Speed chief scientist said the frequency of allergic reactions is still incredibly small, but has increased more than would be expected from other vaccines. Pfizer may need further testing in high-risk allergic populations, suggested Dr. Moncef Slaoui:
The frequency of allergic reactions to Pfizer’s Covid-19 vaccine is higher than would be expected for other vaccines, said Dr. Moncef Slaoui, chief scientific adviser to Operation Warp Speed, on Wednesday. …
“This frequency, as it was yesterday, is higher than you would expect 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 very allergic populations, such as those who need to carry an EpiPen all the time.
What exactly does it mean that the frequency is “higher”? How many serious reactions have been reported? On Tuesday, Slaoui told CNN, the number was in … six. But six of how many?
Over a million and counting, which leads the world:
The United States now leads the world in administered Covid-19 vaccines, with 1,008,025 doses administered in the 10 days since the first doses were released for use, according to the Centers for Disease Control and Prevention.
State vaccination campaigns are launching vaccines from Pfizer Inc. and Moderna Inc., with an initial focus on hundreds of thousands of health professionals across the country who have been battling the virus on the front lines of hospitals. Vaccines require two vaccines weeks apart to provide the highest level of protection.
China, which has several home vaccines, has vaccinated more than 650,000 people and says it has administered 1 million doses. That number could actually be much higher, or at least higher than the US total, as the country provides rare updates on its effort. Russia vaccinated 440,000 people. Both countries took the lead in August, authorizing domestically produced vaccines before they were fully tested.
Six in a million? This is a very small frequency rate, which is why it did not appear in the Phase 3 tests. This population would be about 30,000 people in the active group; if it had produced an unexpected allergic reaction, we would have seen dozens or dozens of serious allergic reactions by now. That is why the CDC and the FDA only granted emergency use authorization to Pfizer and Moderna; they will require further testing to address remaining questions about impacts on specific subpopulations, especially as they arise during EUA vaccinations.
However, there is no reason to stop now. Compare the frequency of allergic response observed so far with the lethality rate of the virus. At your lowest estimate of 0.4% lethality (flu is usually around 0.1%), you would expect to see 4,000 deaths in a population of one million infections. Six serious allergic reactions simply cannot be compared based on risk. An allergic reaction can be deadly, but clearly the numbers show that it is still an extremely rare event, and the injection is a much better bet than remaining unvaccinated.
Finally, some are complaining that the United States will not meet its goal of 20 million vaccinations by the end of the month. This has always been a little ambitious, and the logistics are proving to be complicated – as everyone should know they would be. However, getting a million vaccines in the first ten days is an incredible pace, and we’ve just added Moderna’s second vaccine three days ago. After states define logistics and priority rankings, the pace is expected to increase considerably. If it takes until January 10 or more to reach 20 million, it’s still an incredible achievement.