This Is What It Means If You Got Pfizer & Had No Side Effects, New Study Says
A new study looked into the connection between side effects & antibody response in Pfizer recipients.
Doctors and public health experts spent a lot of time in the early days of the COVID vaccine rollout warning that side effects were to be expected. And while it was reassuring to know that a fever, fatigue, and other mild to moderate reactions weren't cause for concern, what many of us didn't realize was that a lack of vaccine side effects was also not reason to sound an alarm. "When you actually look at the statistics from the [clinical] trials, most people didn't have side effects. A little over 50 percent didn't experience any side effects at all," Thaddeus Stappenbeck, MD, Chairman of the Department of Inflammation and Immunity at Cleveland Clinic's Lerner Research Institute, explained on the hospital's website. But because that wasn't widely known, when people started leaving their vaccination centers feeling fine, they started to worry whether or not the vaccine was working. Over the course of the last seven months, experts have tried to send the message that while side effects are a sign your vaccine is working, no side effects aren't a sign that it isn't. And now, a new study from the Infectious Disease Clinical Research Program (IDCRP) is shedding some light on what that might mean, specifically when it comes to side effects and the Pfizer vaccine.
A team of doctors and scientists from Uniformed Services University of the Health Sciences, Naval Medical Research Center, and the Henry. M. Jackson Foundation for the Advancement of Military Medicine came together to show how the immune response of someone who had no side effects differs from that of someone who had strong ones. In their study, which was posted to the pre-print website medRxiv on July 2 and has not yet been peer-reviewed, the authors explain they wanted to look into the connection due to all of the confusion equating side effects and efficacy.
"During the roll-out of COVID-19 vaccines, it has become commonplace for media outlets and medical professionals to state that presence of symptoms means that a vaccine is 'working.' Although this statement is fundamentally true because vaccines 'work' by inducing inflammatory responses, it also implies incorrectly that lack of symptoms post-vaccination may indicate an absence of appropriate antiviral antibody responses," the authors wrote.
Your immune response to a virus, or vaccine, is measured a variety of ways, but one of the most common is the production of antibodies. Antibodies are "specialized proteins produced by the immune system to identify and destroy foreign invaders, such as bacteria and viruses," An antibody titer blood test is done to determine the presence (qualitative) and amount (quantitative) of antibodies in the blood."
To conduct their study, the research team tested 206 employees from Walter Reed National Military Medical Center for antibodies against the coronavirus before and after they got the Pfizer vaccine. Participants were all healthy, not immunocompromised, and did not test positive for COVID-19 at the time they were enrolled. The researchers also had participants complete a questionnaire about their vaccine-induced side effects after each dose, measuring 12 symptoms' duration and severity on a scale of 0 (not at all) to 4 (a lot). They then conducted antibody tests 37 days on average after their second dose.
When comparing participants' antibody results with their symptom scores, the authors wrote, "We found no correlation between vaccine-associated symptom severity scores and vaccine-induced antibody titers one month after vaccination." They added that the duration of side effects after the first and second Pfizer doses also "revealed no association" with antibody response. "[A] lack of correlation was observed even when adjusting for age, weight, and sex," the authors explain.
Ultimately, the researchers concluded that a "lack of post-vaccination symptoms following receipt of the BNT162b2 [Pfizer] vaccine does not equate to lack of vaccine-induced antibodies one month after vaccination." And that led them to two important conclusions. "First, individuals that exhibit few symptoms after vaccination can be reassured that this does not mean the vaccine 'didn't work.' Indeed, in this cohort individuals with few to no symptoms were just as likely to have developed strong antibody responses as individuals that exhibited substantial symptoms. Second, the immunological pathways responsible for mRNA vaccine-induced [side effects] may not be required for development of robust antibody responses."
It's also worth nothing that in the real world, a large majority of people who've been vaccinated against COVID have not had side effects. In a June Economist/YouGov poll, 75 percent of people in the U.S. said they had no side effects after receiving the COVID vaccine and Pfizer recipients in particular were less likely to have side effects: only 19 percent of people who got the Pfizer vaccine said they had a reaction.
So, if you were among the many who got your Pfizer shots and felt little else but a prick in the arm and some soreness, or maybe even emerged completely scot-free, rest assured that there's no reason to believe the vaccine and your immune system weren't doing their job.