CDC weighs increasing time between vaccine doses to lower risk of heart inflammation

Risk of heart inflammation is lowered if the vaccines are given eight weeks apart, health officials say

U.S. health officials are considering new changes to vaccine guidance that would lengthen the amount of time between doses in order to lower the risk of heart inflammation for immunocompromised people.

The Centers for Disease Control and Prevention (CDC) told a panel of outside advisers on Friday these proposed changes would apply to the Moderna and Pfizer vaccines.

Immunocompromised people, who generally don’t respond as well to vaccines, are the only population advised to get four vaccine jabs.

CDC guidance suggests this group should receive three vaccine doses within two months and a fourth dose around five months after the third. The CDC is now suggesting that immunocompromised people should get their fourth short as soon as three months after the third.

This update would apply to people ages 18 and up who receive the Moderna or Johnson & Johnson vaccine, and people age 12 and up who received Pfizer.

Dr. Sara Oliver, a CDC official, said during Friday’s presentation, that an extended interval appears to reduce the risk of myocarditis. She also said the risk of heart inflammation is lowered if the vaccines are given eight weeks apart.

Although rare, myocarditis is a side effect seen in the Pfizer and Moderna shots and appears to be most common with young men. Most cases are mild and resolve quickly.

Some 33 million people in the U.S., between the ages of 12 and 39, remain unvaccinated, according to Oliver.