New research suggests increasing the interval between vaccine doses or using a single dose may significantly lower the risk of heart inflammation caused by mRNA COVID-19 vaccines. Yet some cardiologists are concerned about asymptotic myocarditis and say any risk of heart inflammation in a population group that’s not at risk of experiencing severe COVID-19 is too much.
In a February peer-reviewed paper published in NPJ Vaccines, researchers in Hong Kong observed a significantly lower cumulative incidence of carditis, or heart inflammation, among adolescents who received their second vaccine dose more than 56 days after their first dose compared with those who received their second dose within 21 to 27 days. A second analysis showed that increasing the time between the first and second vaccine doses decreased the risk of heart inflammation by 66 percent.
Researchers compared the risk of carditis between standard and extended interdose intervals in 12- to 17-year-olds who received two doses of Pfizer’s COVID-19 vaccine.
