Advisers from the US Centers for Disease Control and Prevention, or CDC, on Wednesday will discuss reports linking heart inflammation in young people to COVID-19 vaccines.
On May 20, a group of CDC vaccine advisers posted a report on the CDC website saying that there had been "relatively few reports" of myocarditis after vaccination
The CDC's Advisory Committee on Immunization Practices is scheduled to hear details of some 300 or more reports of myocarditis and pericarditis in teenagers and young adults who have recently received the mRNA type of vaccines made by the Pfizer-BioNTech partnership and Moderna, according to CDC Director Rochelle Walensky.
Walensky said at a White House briefing last week that in the "vast majority" of cases the inflammation went away.
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Long before the pandemic, thousands of cases of myocarditis－inflammation of the myocardium in the heart－were diagnosed around the world every year. In March, the US Department of Defense started to receive reports of myocarditis among vaccinated members of the military, according to the military.com platform.
On May 20, a group of CDC vaccine advisers posted a report on the CDC website saying that there had been "relatively few reports" of myocarditis after vaccination.
On June 1, the CDC advisers changed their statement, saying "there was a higher number of observed than expected myocarditis/pericarditis cases in 16-24-year-olds".
"We clearly have an imbalance there," Tom Shimabukuro, deputy director of the CDC's Immunization Safety Office, told NBC News.
Myocarditis occurred typically within several days of vaccination and more often after people got the second vaccine shot, according to the CDC. The symptoms included fever, fatigue, shortness of breath and a particular type of chest pain.
The CDC said that among the patients recovering, more than 80 percent of them improved on their own.
Effect on brain
Also causing concern is a study suggesting that COVID-19 might shrink parts of the brain.
The study's authors identified "significant effects of COVID-19 in the brain", finding a loss of brain tissue known as gray matter in some regions of the brain that affect a person's sense of taste and smell.
The authors also identified consistent abnormalities among COVID-19 survivors in a part of the brain that deals with memory.
"It's very concerning because it does suggest that the virus could be having a direct effect on certain portions of the brain," former FDA commissioner Scott Gottlieb said on a recent CBS News program.
The study, which reviewed 394 people's brain scans before they were infected with the coronavirus, was conducted by scientists at the University of Oxford and Imperial College in the UK and the National Institutes of Health in Maryland. It was posted on MedRxiv, an online archive, on Sunday.
The administration of US President Joe Biden on Monday announced a plan to allocate an additional 55 million COVID-19 vaccine doses to other countries by the end of this month.
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The announcement comes as the vaccine supply in the US is outpacing demand.
While roughly 65 percent of adults in the US have received at least one shot of a COVID-19 vaccine, many low-income nations haven't reached the 1 percent mark for vaccinations.
"Unfortunately, as usual, low-income countries continue to be at (the) back of the line or at the mercy of high-income countries," Krishna Udayakumar, director of Duke University's Global Health Innovation Center, told the Scientific American journal.
