The federal government has authorized a third dose of either the Pfizer or Moderna vaccines for people with weakened immune systems.

This important news applies to Arizonans with moderately to severely compromised immune systems. These individuals are especially vulnerable to COVID-19, and an additional vaccine dose for them could help prevent serious illness and death. A recent study suggested that nearly half of breakthrough cases in the U.S. requiring hospitalization are immunocompromised individuals.

Today’s recommendation from the Centers for Disease Control and Prevention (CDC) covers a range of conditions. Among them are those with organ or stem cell transplants, those with advanced or untreated HIV infection, those receiving cancer treatment, and those taking medications that weaken the immune system. The CDC estimates that around 3% of those eligible for vaccination are in these groups, which works out to about 150,000-200,000 among Arizonans 12 and older.

These third doses will be handled the way people are now receiving COVID-19 vaccinations: at pharmacies, clinics and other providers. If you are among those affected by this updated guidance, I encourage you to contact your healthcare provider to answer any questions you may have. Vaccine providers can answer questions as well.

Here is what the Food and Drug Administration (FDA) and CDC and Prevention have authorized:

  • For immunocompromised individuals, federal officials recommend an additional (third) dose of Pfizer-BioNTech COVID-19 vaccine for age 12 and older and the Moderna vaccine for those 18 and older. Both of these are mRNA vaccines.
  • Providers should attempt to match the additional dose type to the two-dose series that person received; however, using the other vaccine for the additional dose is permitted if circumstances warrant.
  • The additional dose of mRNA COVID-19 vaccine should be administered at least 28 days after the second  mRNA COVID-19 vaccine dose.

This news has many vaccinated people asking if and when the federal government will recommend a booster vaccine for everyone. That decision is pending at the federal level, but the good news is studies continue to show that all three approved vaccines continue to offer protection from COVID-19 infection long after people get them.

There is ample vaccine throughout Arizona to accommodate immunocompromised individuals and those who have yet to get vaccinated. Vaccines are safe, free and highly effective. I encourage you to find a provider at and get vaccinated today.