Members of a Food and Drug Administration vaccines advisory committee have expressed concerns that COVID-19 vaccines under consideration address mild COVID-19 only.

A panel of independent clinicians, scientists and other experts met last week to discuss guidance for drugs the federal government has found the most promising. The nine-hour meeting was streamed on YouTube as part of the agency’s effort at transparency as it attempts to gain public trust in the vaccine review process.

Many committee members said the trials and resulting guidance may be too focused on mild disease, according to legal news outlet Law360. This may leave the problems of severe COVID-19 illness and mortality unanswered, they said.

The efficacy measures in the guidance are “biased, skewed towards mild disease. And that is a concern,” said Luigi Notarangelo, M.D., of the National Institute of Allergy and Infectious Diseases.

Since severe disease and death occur at a high rate in minorities, a vaccine that doesn’t do enough may also reinforce the idea that there is disinterest in these populations’ health and welfare, added James Hildreth, Ph.D., M.D., president and CEO of Meharry Medical College.

But other committee members pushed back, noting that even among the large number of participants in these clinical trials, severe cases will be rare. They contend that a focus on the worst cases would require an untenable number of participants, Law360 reported.

What’s more, “there simply does not exist an example in vaccinology of vaccines that are effective against mild disease that are not more effective against severe disease,” argued Philip Krause, M.D., deputy director of the FDA’s Office of Vaccines Research and Review.

The Department of Health and Human Services and the Department of Defense have entered agreements with top drugmakers to manufacture the experimental vaccines while they’re still being tested in clinical trials. The goal is for the drugs to be ready for immediate distribution if trial results are positive and the FDA approves their use.

On Friday, drugmakers AstraZeneca and Johnson & Johnson announced that they were resuming their COVID-19 vaccine trials in the United States. The trials had been halted for review as standard practice after a volunteer in each trial became ill.