The U.S. Centers for Disease Control and Prevention (CDC) has updated its coronavirus vaccine guidance, now saying that those who are considered immunocompromised might need another shot, which in some cases would be their fourth dose.

It was back in August when the CDC recommended that immunocompromised individuals who were vaccinated with either the Pfizer-BioNTech or the Moderna mRNA vaccine should get another dose. Do take note that the extra shot, though, was not considered a booster, but rather an integral part of their primary vaccination series.

Recent data from the CDC are indicating that booster shots are needed for certain populations. “Studies show that after getting vaccinated against COVID-19, protection against the virus may decrease over time and be less able to protect against the Delta variant. Although COVID-19 vaccination for adults aged sixty-five years and older remains effective in preventing severe disease, recent data suggest vaccination is less effective at preventing infection or milder illness with symptoms,” the agency writes.

Currently, the U.S. Food and Drug Administration has authorized booster shots of all three available vaccines for certain people, which include the elderly and those who are immunocompromised.

Moderately to severely immunocompromised individuals include people who are in active treatment for cancers, certain organ transplant and stem cell recipients, those with advanced or untreated HIV, and those who take high-dose corticosteroids or other drugs that could suppress their immune systems.

The CDC has estimated that between 2 and 3 percent of the U.S. population fit into this category. 

“We know that six months after you reached a good level of protection, your protection has waned … and we need to boost that,” Dr. Dorry Segev, professor of surgery at Johns Hopkins University, told NBC News. “That’s for people with normal immune systems and people who are immunocompromised.” 

However, he did admit that not all immunocompromised individuals will need a fourth vaccine dose.

“Out of the eleven million immunocompromised people in this country, some of them were fine with two doses,” Segev noted.

“Some of them were not fine with three doses. Some of them do need a fourth dose,” he continued.

According to the peer-reviewed journal The Lancet, a group of leading U.S. and international scientists, including those from the FDA and the World Health Organization, recently contended that boosters are not needed currently for the general public.

The experts were aware of the fact that vaccine effectiveness against the coronavirus likely wanes over time but did note that protection against severe disease could persist.

“Current evidence does not, therefore, appear to show a need for boosting in the general population, in which efficacy against severe disease remains high,” the team writes.

Ethen Kim Lieser is a Washington state-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.

Image: Reuters