USA – Moderna COVID-19 vaccine generates long-lasting immune memory

People who received low doses of the Moderna COVID-19 vaccine had strong immune memories of the virus six months after being fully vaccinated. Those carrying cross-reactive T cells from earlier exposure to other coronaviruses had greater immune responses after vaccination. The findings shed light on how lasting immunity develops after vaccination.

The Moderna and Pfizer mRNA vaccines against COVID-19 have shown greater than 90% effectiveness soon after the second dose. Studies suggest that protective immunity remains high, with only slight decreases, over six months. However, scientists are still working to understand how immunity against the virus develops after vaccination and changes over time.

Researchers believe that strong responses from both neutralizing antibodies and immune cells called T cells are necessary for immunity. Memory T cells linger in the body to recognize and protect against previously encountered pathogens. Recent studies indicate these may be crucial for lasting protection against COVID-19…