Image of Anthony Fauci, director of NIAID; Image credit: NIAID

With COVID-19 cases up and deaths rising, the United States is working to swiftly approve vaccine booster shots for people with weakened immune systems, federal health officials said in a Thursday press briefing.

“We are working on that as quickly as possible, because for us, and for the individuals involved, it is a very high priority,” Anthony Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases and chief medical advisor to the president, said. 

The delta variant appears to have contributed to a 43% uptick in U.S. cases over the past week, and a 39% increase in seven-day average daily deaths, according to the Centers for Disease Control and Prevention. People who are immunocompromised may have a weak immune response to COVID-19 vaccines, the agency reports. Among others, those at risk may include patients on hemodialysis, those who have a transplanted organ, and people who are being treated with certain chemotherapy drugs or other immunosupressant medications.

The easiest way to prevent new coronavirus gene variants from replicating and overtaking the protections of the current COVID-19 vaccines is to focus on getting more people vaccinated, Fauci said. Good vaccine uptake effectively blocks the rise of variants that could be problematic, he said.

Vaccine protection for immunocompromised patients might be further bolstered by an additional vaccine shot. But gathering the evidence needed to recommend boosters for the especially vulnerable in a safe and effective manner can take time, CDC Director Rochelle Walensky, M.D., said in the press briefing. Federal health officials are reviewing the combined evidence from immune response data, antibody and clinical trial data, and vaccine efficacy data from cohort groups such as the nursing home population, she said.

“The ultimate end game” is vaccinating the 93 million eligible but unvaccinated Americans, Fauci said. “If we do that in the immediate, intermediate and long term, and do the mitigation [measures] right now, we will turn the delta surge around.”

Moderna shoots for booster availability in the fall

Vaccine maker Moderna, meanwhile, is aiming to have a booster shot ready this fall, CEO Stephane Bancel told CNBC Wednesday. That’s despite new evidence showing that the company’s shots maintain 93% efficacy six months later — little changed from the 94% protection found in the drug’s original clinical trials, Reuters reported.

“I want to make sure there are boost vaccines available in the fall so that we protect people as we go into the next fall and winter season in the U.S.,” Bancel said on CNBC’s “Squawk Box.”

In early July, drugmaker Pfizer met with federal scientists and regulators to petition to have a third dose of its COVID-19 vaccine added to the drug’s two-shot schedule. Data in an ongoing trial showed that a booster dose given six months after the vaccine’s second dose could significantly improve immunity to SARS-CoV-2 variants, Pfizer reported. The CDC argued that it needed more data on the number of infections breaking through vaccine protection.