Immunocompromised People Were Not Included In Initial Coronavirus Vaccine Trials


Many people with a weakened immune system have a higher risk of severe COVID-19.

This includes people with cancer or HIV or those who have organ transplants. Also included are bone marrow recipients, and people taking corticosteroids or other medicines that suppress the immune system.

Public health experts have recommended that people who are immunocompromised take steps to avoid being exposed to SARS-CoV-2, the coronavirus that causes COVID-19.

This includes staying home as much as possible, practicing physical or social distancing, and wearing a cloth mask when around others.

But what about the coronavirus vaccines? Will these offer another level of protection for people who are immunocompromised?

Two vaccines — Pfizer/BioNTech’s and Moderna’s — are likely to receive emergency approval this month from the Food and Drug Administration (FDA). Preliminary data suggests the vaccines can protect against symptomatic coronavirus infection.

However, these vaccines won’t be approved initially for use in people who are immunocompromised. This group, though, could still benefit from widespread coronavirus vaccination.

“We will eventually be able to offer protection to [immunosuppressed people], either through direct vaccination or by indirectly protecting them through herd immunity,” said Dr. Edward Jones-Lopez, assistant professor and infectious diseases specialist at Keck Medicine of University Southern California.

Immunocompromised not included in initial vaccine trials
All vaccines have to go through clinical trials before they can be approved for use by the FDA. The initial coronavirus vaccine trials have been done in the “general” population.

This includes healthy, younger adults, as well as older adults and some people with well-controlled health conditions such as diabetes or heart disease.

But these trials have excluded particularly high-risk or vulnerable populations such as children, pregnant women, and the immunocompromised.

Studies involving these higher-risk groups are generally done only after the initial vaccine studies have finished.

“Once the vaccine is deemed safe and effective within the general population,” said Jones-Lopez, “other studies are done that target these specific high-risk populations.”

Though most immunocompromised people were excluded from the initial coronavirus vaccine trials, one group was included — people 65 and older.

In general, older adults have less effective immune responses, including poor responses to vaccines. That’s why this group gets a higher-dose flu vaccine each year.

Jones-Lopez said that for the other groups — especially those who are severely immunocompromised — there isn’t enough data to know if the coronavirus vaccines will be appropriate for them.

“I would say we are one or two studies away from finding this out,” he said.

Another issue with vaccinating people who are immunocompromised is that some vaccines contain live, weakened virus or bacteria. This, however, is not the case with the two vaccines most likely to be approved first.

These types of vaccines don’t generally cause illness in healthy people but can be riskier for those with a weakened immune system.

For example, the chickenpox and herpes (zoster) vaccines aren’t recommended for people with severely compromised immune systems.

Of the more than 100 vaccines being developed to protect against COVID-19, only a few use a live, attenuated coronavirus virus. These vaccines, though, are all still in the very early stages of development.