With vaccination programs progressing across the country, the general public is closing in on its turn for a poke. Washington State University professor and pathologist Guy Palmer said this is no time to worry about “efficacy,” and there is little cause for concern when it comes to adverse reactions.
Palmer, who is also founding director of WSU’s Paul G. Allen School for Global Animal Health, said while percentages representing the efficacy or effectiveness of vaccines developed to combat COVID-19 have been in headlines lately, people should resist the urge to compare the number assigned to, say, Johnson and Johnson’s vaccine with the one created by Pfizer.
For one thing, Palmer said most of these efficacy studies were conducted in different seasons and among different populations, and these disparities likely had an effect on the data.
Further, while the goal of any vaccine is to prevent severe disease, hospitalization and death — what Palmer called “the big three” — he said researchers could not directly study a given vaccine’s effectiveness at preventing one of these three endpoints without taking a lot of time. Rather than conduct a protracted study and wait for participants to fall seriously ill, become hospitalized or die, he said researchers instead tested how well their shot prevented detectable infection. He said the thought is if a vaccine prevents infection, then it will prevent the more serious outcomes.
He also noted that these efficacy numbers were developed in clinical trials but now that vaccines are becoming more widely available, researchers are starting to receive more reliable insight on their performance.
“We’re starting to get the data on how good they are at preventing severe disease, hospitalization and death and the data to date is: they are amazingly good at that,” he said. “ They are basically preventing — as in zero cases — severe disease, hospitalization and death and they’re just remarkably effective with that.”
Ideally, Palmer said, vaccines will also interrupt the spread or transmission of a disease.
He said it is true that the increasing availability of vaccines will make it so far fewer people are capable of spreading COVID-19, and those vaccinated individuals who do become infected won’t be nearly as contagious for as long as someone who is not vaccinated. However he warned on the individual level it’s difficult to tell how well they responded to the vaccine or how likely they are to infect others. People may feel a sense of relief after receiving their inoculation but Palmer said now is not the time for the public to let its guard down.
Palmer said those worried about having an adverse reaction to one of the vaccines may be comforted to know such reactions are fairly rare and in many cases are a sign the vaccine is working. He said truly serious reactions are most often the result of anaphylaxis — an allergic reaction. These cases are especially uncommon he said, but this is why patients are asked to wait under observation for 15 to 30 minutes after receiving a shot.
Palmer said the most common reactions to a vaccination might feel like the crummy beginnings of a cold but those symptoms last at most 48 hours and are most likely evidence of a person’s immune system going to work.
“Part of that immune response are things like, fever (and) feeling kind of lethargic. That’s basically what most individuals are seeing,” he said. “It’s not something that’s telling you there’s a problem with the vaccine, it’s actually telling you the vaccine is doing exactly what it’s supposed to do. It’s stimulating your immune response.”
Even with heavy participation in vaccination programs, Palmer said at the moment, it appears very unlikely COVID-19 will be eradicated by the effort. More likely, he said, is the coronavirus that causes COVID-19 will join its cousins which cause the common cold in being a perennial but manageable nuisance.
“We’re not going to get 100 percent vaccination or to the threshold that we can drive it out of the population, and the variants that continue to develop will continue to circulate,” he said. “However, we may be to the point where — and I think our goal is — we want to make this like the other four circulating coronaviruses; inconvenient but not life-threatening.”
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