Monitoring vaccine side effects

Sandra Lindsay, a nurse at the Long Island Jewish Medical Center in New York, became the first American on Monday to receive a COVID-19 vaccine (besides those participating in medical trials). Pfizer, in association with BioNTech, began rolling out the shot just days after the U.S. Food and Drug Administration approved it on Dec. 11. “I believe this is the weapon that will end the war,” New York Gov. Andrew Cuomo said while watching Lindsay’s immunization over video conference. “This is the beginning of the last chapter of the book.”

The next day, FDA officials indicated a second vaccine from the drugmaker Moderna would likely receive emergency use authorization soon. The agency’s advisers meet Thursday to review the research into the vaccine and make a recommendation.

Some nine months after the novel coronavirus upended lives around the world, manufacturers and officials are ramping up production and working out ways to distribute hundreds of millions of vaccine doses. The FDA has not cited any major safety concerns with the medication so far, but drugmakers warn those lining up for shots will likely feel some side effects.

For biotechnology companies like Moderna, the creation of the vaccine proved to be the quickest part, but testing took months to complete. Moderna formulated its vaccine in January days after Chinese researcher Yong-Zhen Zhang published the virus’s genetic sequence. By Feb. 24, just weeks after the United States recorded its first COVID-19 deaths, Moderna shipped its first doses to the National Institutes of Health for a Phase 1 study. In the intervening months, Moderna and other companies have raced to demonstrate the safety and efficacy of their formulas.

In trials, both Moderna and Pfizer reported high numbers of mild and moderate side effects that typically lasted just a few days. Nine out of 10 people injected with Moderna’s vaccine suffered ancillary symptoms, and of those, more than 90 percent reported some pain at the site of injection. More than half experienced muscle pain or fatigue, and over 60 percent suffered headaches. According to Moderna, most of the side effects lasted just a few days. Recipients of the Pfizer vaccine reported similar experiences.

Health agencies are keeping an eye out for more significant side effects. The U.K. Medicines and Healthcare Products Regulatory Agency issued guidance this week saying patients with a history of allergic reactions to vaccines, food, or medicine shouldn’t receive the Pfizer shot. Officials with the agency reported two cases of anaphylaxis in the early days of the vaccine rollout. Two Alaskan health workers have also experienced allergy-like reactions. All of the affected individuals recovered.

The FDA also recommended watching for signs of Bell’s palsy, a weakening of muscles on one side of the face, in patients receiving the vaccine. Four trial participants developed the condition, but researchers said they didn’t have enough information to demonstrate a causal link between the vaccine and the incidents. All of those affected have recovered.

Both the Pfizer and Moderna vaccines require two doses separated by three to four weeks. Pfizer’s vaccine requires dry ice to keep the vaccines at temperatures of minus 94 degrees Fahrenheit. Moderna says its vaccine can be stored at minus 4 degrees Fahrenheit.

Frontline healthcare workers are receiving the vaccine first, along with nearly 3 million mostly older Americans living in long-term healthcare facilities like nursing homes. The FDA said Americans receiving the Pfizer vaccine will have strong protection about a week after the first dose and best protection a week after the second dose. The two doses are 95 percent effective at preventing the disease, the company reported.

Scientists say they don’t know how long the vaccines protect from COVID-19. If the immune response to the vaccine is similar to that from contracting the virus, the benefits may last for months or even years. In a November study, scientists found the number of immune cells capable of fending off COVID-19 to be quite high even six months after infection. They suggested the immune memory of patients who contract the coronavirus might offer years of protection.

“That amount of memory would likely prevent the vast majority of people from getting hospitalized disease, severe disease, for many years,” La Jolla Institute of Immunology virologist and study co-author Shane Crotty told The New York Times.