In my last newsletter, I briefly discussed antibiotic resistance; you can read it here.
Disclaimer: All information in my newsletters are for educational purposes only and should not be substituted as medical advice. Please consult with your doctor or a healthcare professional if you have concerns or questions about vaccines.
At the end of April, my family and I received our second dose of the Moderna COVID-19 vaccine. I was worried because I had three final exams in the following days, and I did not want the possible side effects to impact my performance while studying and taking them. An hour after I received the dose, I felt a sore arm—and that was it. My dad and brother, on the other hand, were sick for the next two days, unable to sleep, experiencing every known side effect.
Many are curious as to why certain people are susceptible to varying reactions after receiving either dose of the COVID-19 vaccine while others are not. Infectious disease experts continue to work diligently to reassure the public that having flulike symptoms after receiving the vaccine is a sign of the immune system responding. Experiencing fatigue, a headache, chills, and other symptoms is the body’s visible sign of building protection against the SARS-CoV-2 virus. This correlation could also lead people to conclude that if your body did not have any reaction, then it was failing to build immunity against the virus. However, many infectious disease doctors reassure individuals that most people will have protection even if you do not have symptoms.
Dr. H. Cody Meissner, chief of the pediatric infectious diseases unit at Tufts University School of Medicine in Boston, reiterates,
“I don’t think someone should correlate the extent of their reactions to the vaccine with protection from the infection. We know that people who don’t respond to a vaccine in terms of the side effects still are well protected. The vaccines work even if you don’t have fatigue and headache and fever and muscle pain and joint pain.”
More research is needed to understand what the presence or absence of vaccine side effects can say about the strength of one’s immune system.
What do we know?
A study at the University of Pennsylvania found that individuals who reported heavy side effects after receiving either the Pfizer/BioNTech or Moderna vaccine had moderately higher antibody levels than those who did not have heavy side effects. All people in the study, however, did have good immune responses. It was also found that individuals who previously recovered from COVID-19 received a great antibody response from the first dose of the vaccine, but little benefit from receiving the second dose. Those who did not have COVID-19—referred to as COVID naïve—benefited significantly from the second dose; in fact, they did not receive full immunity until the second dose. Nevertheless, it is recommended for everyone to receive both doses of the vaccine to ensure full protection regardless of whether or not they have had the disease.
In current studies, age is shown to be a significant indication of who is likely to experience side effects. Those over age 65 are less likely to experience side effects than those younger; older adults usually have less robust immune systems. Additionally, women are more likely than men to undergo a reaction which is most likely due to hormonal or weight differences, explains Dr. Kathryn Edwards, a professor of pediatrics and a vaccine researcher at Vanderbilt University School of Medicine in Nashville.
Some doctors believe that genetics can also have an influential role. Dr. Paul Offit, the director of the vaccine education center at Children’s Hospital in Philadelphia says,
“I am sure that our genes at some level determine differences in these responses.”
The long-term impacts of COVID-19
For the past year, many have been involved in aggressively addressing and treating the short term symptoms of COVID-19. However, a new study from the University of Michigan suggests an urgent need to understand and treat “long-haulers,” people who still experience symptoms months after their diagnosis. This is known as post-acute sequelae of SARS-CoV-2 infection (PASC); symptoms include extreme fatigue, shortness of breath, and chronic loss of tase or smell. While public health experts, doctors, and scientists are trying to end the pandemic, there should also be an organized effort in trying to understand the long-term symptoms individuals experience in order to provide better clinical management and treatment. 53% of people who recovered from COVID-19 experienced symptoms 30 days after their initial onset, while 35% had symptoms 60 days after their initial onset. The data was gathered from a project I’ve been working on since October 2020, known as the Michigan COVID-19 Recovery Surveillance Study (MI CReSS). This is a joint study between the U-M School of Public Health and the MI Department of Health and Human Services. Read more about our findings here.
If you have any questions, please email me at reemlfawaz@gmail.com.
Interesting piece Reem. My wife and her indentical twin sister had completely opposite reactions to Moderna second shot, even though they went to get that second shot together. Been interesting to see the reactions of different people.