Covid-19 Vaccine Side Effects Vary by Type, Remain Mild

With a third Covid-19 vaccine now authorized in the United States, distribution is set to ramp up in the coming weeks. Courthouse News talked to medical experts about possible vaccine side effects, and what to know before booking an appointment. 

Volunteers and health care workers carry out a mass vaccination campaign at the former site of a Sears department store in a partnership with San Diego County, the city of Chula Vista and Sharp HealthCare. (Courthouse News photo/Barbara Leonard)

(CN) — As the United States closes in on three months of the Covid-19 vaccine rollout, more than 57 million people have been able to receive at least one shot. The recent authorization of the Johnson & Johnson vaccine means more Americans will be able to make an appointment soon. 

Compared to the previously approved Pfizer and Moderna vaccines, based on messenger RNA, the J&J vaccine works slightly differently. As a result, the side effects expected may vary, too — but many reactions, like fluish symptoms, are common to all three vaccines. 

The main side effect patients report is pain around the injection site, said Kim Litwack, professor and dean of the University of Wisconsin-Milwaukee’s College of Nursing. 

“This is true for dose one and two,” Litwack explained — and it can occur with the one-dose J&J vaccine too. 

When a vaccine is injected, the body’s immune response jumps into action, responding to the presence of a foreign entity. So it follows that the response may be most intense around the source of the intruder: a needle in the arm. 

Fatigue, headaches, muscle and joint aches and fever are all potential side effects as well. In short, it might feel like you have the flu. Those symptoms are similar in all vaccines, but in the two-dose vaccines, they are more common after the second shot. 

Pain can be managed with acetaminophen, like Tylenol, or ibuprofen, Litwack said. Rest and drinking fluids can help with fatigue and fever. 

However, you shouldn’t premedicate before heading to a vaccine appointment, said Todd Brown, instructor and vice chair of Northeastern University School of Pharmacy’s Department of Pharmacy Practice. 

“You shouldn’t take something before getting the vaccine,” Brown explained, “because that depresses the immune system in the body” — meaning the vaccine may not work as effectively. 

Side effects should all be short-lived: They typically start well within a day of getting vaccinated, and may last up to three days. 

Adverse Reactions

This Dec. 2, 2020 photo provided by Johnson & Johnson shows vials of the COVID-19 vaccine in the United States. (Johnson & Johnson via AP)

As with any medicine, there’s a possibility of having an allergic reaction to a Covid-19 vaccine. 

Allergic reactions could be more common with the Moderna and Pfizer vaccines, Brown explained, because of the technology used to develop them, which relies on genetic material called mRNA. 

While researchers say that mRNA opens up new possibilities in medicine, the fragile material easily breaks down. To protect the mRNA-based vaccines, scientists bubble-wrapped the Pfizer and Moderna vaccines at the molecular level, packaging them in lipid nanoparticles, or tiny globs of fat. 

The chemical that makes up the lipid molecules, polyethylene glycol — which is also used to make laxatives — seems to be causing most allergic reactions to the vaccines. The Pfizer and Moderna vaccines are the first mRNA-based vaccines authorized for use, “so that’s why it’s the first time we’re seeing this type of thing,” Brown explained.  

Even so, the risk of vaccine allergy is “extremely low,” Litwack said. In data submitted to the Centers for Disease Control and Prevention in January, there were 2.1 cases of anaphylaxis per million doses of the Moderna vaccine, and 6.2 cases for the Pfizer vaccine. 

“As more doses are given,” Litwack said, “this rate appears to be dropping even lower.”

Most reactions occurred within 15 minutes of receiving the vaccine, and most people who had a reaction also had a history of severe allergies or anaphylaxis. 

“These vaccines are extremely safe,” Litwack said. 

While the J&J vaccine doesn’t have the same potentially allergenic lipids, its recent introduction leaves some room for unknowns. Experts say it’s too soon to say whether J&J vaccine side effects will differ from the others in the U.S. in a meaningful way. 

One potential adverse side effect of the J&J vaccine is the development of blood clots, which a small number of people experienced in clinical trials. In study participants who received a vaccine, there were 15 reports of blood clots, compared to 10 in the control group who received a placebo. There were also six reports of tinnitus, or ear ringing, compared to zero in the control. 

However, the FDA said current data is “insufficient to determine a causal relationship between these events and the vaccine.” 

Based on outcomes so far for Moderna and Pfizer vaccines, it’s unlikely there will be surprises with the J&J vaccine. During the recent FDA meeting where experts endorsed the J&J vaccine, several panelists expressed relief and growing comfort in the process, after seeing the outcome of the first two vaccines. 

“We are very comfortable now with the procedure, as well as the vaccines we are approving,” said Dr. Arnold Monto, chair of the panel and an epidemiologist at the University of Michigan School of Public Health.

When side effects do occur, there shouldn’t be any surprises either: Unlike with long-term drugs, most vaccine side effects happen right away, Brown said. 

Plus, he pointed out, side effects can be seen as a positive thing: “It actually demonstrates that the immune system’s working,” Brown said, and that the body is building up an immune response.

It’s possible that ramping up the immune system can even help people who previously recovered from Covid-19, but still experienced lingering symptoms, feel better. 

“[T]here have been some reports in the literature of patients with persistent symptoms improving after getting the Covid vaccination,” Litwack said. 

“The data is not yet there to support this,” she continued, “but one theory suggests it might point to lingering fragments of virus that remain in the body after infection, which continue to irritate the immune system. After vaccination, the body responds by building more antibodies, which may finally rid the body of these viral fragments.”

Another theory, Litwack said, is that the vaccine simply boosts the immune system overall. More research is needed to confirm the beneficial effect for Covid-19 survivors, she said, but “those who do experience lingering symptoms would appreciate that being the case.”

Toward Herd Immunity 

A man gets the coronavirus vaccine at an outdoor vaccination site at Lakewood Ranch Wednesday, Feb. 17, 2021, in Bradenton, Fla. (AP Photo/Chris O’Meara)

Ultimately, the goal of vaccination is the end of the pandemic. That effort is being sped up by having multiple versions of a Covid-19 vaccine — even despite the fact that J&J doesn’t have efficacy numbers as high as the super-effective Moderna and Pfizer vaccines. Those come in around 95%, while J&J has been reported to be 72% effective in the U.S.

Perfection isn’t the goal when it comes to vaccination to achieve herd immunity, Brown explained. 

“No vaccine is 100% effective,” Brown said. “But if you live in a community that is protected — if everyone around you has gotten the vaccine — then that community has achieved herd immunity, and that’s much more effective in getting rid of a virus or an infection.” 

Consider the flu vaccine. While it isn’t directly comparable because it contains several strains of influenza, the CDC reports that the vaccine reduces illness by a figure between 40% and 60%. 

Herd immunity means stopping Covid-19’s rapid spread and preventing rampant mutations that could be vaccine-proof beyond just individual protection. 

“So that’s really what we want to get to,” Brown said. People are “much better off getting whatever vaccine they can get into their arm, as soon as possible.”

For those who don’t need any convincing — like those who visit the vaccine clinic where Litwack works — the hard part may be waiting for a shot to become available. 

“Folks that show up to vaccine clinics want the vaccine,” Litwack pointed out. “The biggest question, by far, is when can my (fill in the blank family member — sister, son, daughter) get vaccinated.” 

Those same patients tend to be well-informed about the vaccine and side effects. Some also ask Litwack and colleagues if they have a sticker that says, “I got mine,” so they can wear it or post on social media. 

“Like the ‘I Voted’ sticker, it is worn with pride,” Litwack said. “People want to do their part in fighting this pandemic.”

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