Analysis: Understanding the new policy authorizing extra Covid vaccine doses for the immunocompromised

This much is clear: Some people in the United States with medical conditions that have compromised their immune systems are now eligible for a third dose of Covid-19 vaccine.

But the new policy from U.S. health officials, announced late last week, came together in a hurry. It addresses some questions but leaves a number unanswered, in some cases because there are no data on which to base a decision.

Some experts believe the new policy may also have created a loophole big enough to allow easier access to a third dose for non-immunocompromised people who are trying to find ways to get one.

“I worry very much that this is going to lead to vaccination chaos,” Michael Osterholm, director of the University of Minnesota’s Center for Infectious Diseases Research and Policy, told STAT.

Why the policy to begin with? Studies have shown that some people who are moderately to severely immunocompromised do not get much if any protection from the regular vaccine regimens. A study released as a preprint last month, meaning it has not been peer-reviewed, showed that a substantial portion of vaccinated people who ended up in hospital for Covid were immunocompromised. ...