Who can have a third dose of a COVID vaccine?

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August 13, 2021

I just sat in on a meeting of the CDC’s Advisory Committee on Immunization Practices (ACIP) meeting regarding an ADDITIONAL dose for moderately to severely immunocompromised patients.  There was a very broad range of experts, covering the fields of pediatrics, internal medicine, infectious diseases and immunology.  Here are the main takeaways:

– Yesterday, 8/12/21, the FDA authorized an additional vaccine dose only for moderately to severely immunocompromised people.  The ACIP today voted in agreement with that decision.

– Almost 3% of the U.S. adult population is considered immunocompromised.  The new recommendation focuses on them because:

*They are more likely to get severely ill

*There is increased risk for prolonged infection and shedding -> putting others at risk

*They have lower neutralizing antibody titers, suggesting they won’t mount an adequate response when they encounter the virus.

*Because of these factors, they are more likely to transmit the virus to household contacts.

– This is NOT called a booster dose.  It is an ADDITIONAL dose to increase the immune response in those who might not have mounted enough of a beneficial response to the first two doses.  A BOOSTER dose would be one that might be given after the response wanes – just like we routinely give a tetanus booster dose every 10 years, or after 5 years if you sustain an injury.  The question of a booster dose remains under discussion.

– The recommendation is regarding those who received 2 doses of Moderna or Pfizer, not for those who received the single dose of J&J.  They mentioned that the CDC and FDA are working on the latter.  There is less information available because that vaccine was rolled out later than the others.

– A third dose is recommended at least 28 days after the 2nd dose of the initial series.  It should be the same  brand as the first 2 doses if possible.

– Many people have asked to have their antibody levels checked.  None of the antibody tests to check vaccine response is authorized or recommended.  A third dose would be given on the basis of a person’s clinical situation — i.e. being at high risk of severe covid due to a moderate to severe immunocompromised status.  Antibody levels will not be checked.


*Active treatment for solid tumor and blood malignancies

*Solid organ transplant and use of immunosuppressive therapy

*Stem cell transplant within the past 2 years 

*Known immunodeficiency not related to medications – e.g., low antibody levels, no spleen

*Advanced or untreated HIV infection

*Prednisone at doses at 20 mg or higher, chemo, certain immunosuppressants like TNF blockers and other biologics.  People with autoimmune diseases should check with their rheumatologists about these.

– Immunocompromised individuals should be able to go to a pharmacy to get their 3rd dose.  They will not need written documentation of their medical situation. 

– There was no mention of any age distinctions for the current recommendations – being of a certain age does NOT qualify as a significant immune issue.  

– Similarly, chronic medical conditions, like heart disease, diabetes, etc, would NOT qualify under this new recommendation.  Nor would living in a longterm care facility.

– Even with a third dose, it is important for those with immune compromise to mask around people not in their household, distance at 6 feet or more,  and avoid crowds and poorly ventilated indoor spaces.

– In studies that are available so far, response to the 3rd dose varies depending on the underlying illness.  In some groups, up to 50% developed what we think is an adequate antibody response.  It is too early to say if that increased antibody response will result in a decrease in illness.

– There were no critical side effects from the third dose; they were mostly mild, similar to the first 2 doses.  

– Everyone 12 years or older should be vaccinated, ESPECIALLY close contacts of immunocompromised individuals.  

– As of August 9, 2021, there have been over 35 million cases of COVID illness in the U.S.  The recent 7-day rolling average is over 100,000 cases per day, with over 600 DEATHS per day.  The vast majority of hospitalizations and deaths are in the unvaccinated population.  This is totally avoidable in a country such as ours with an abundant supply of vaccine.  

–  We will continue to have outbreaks here and abroad, with new variants, potentially even more contagious and harmful than Delta, until the vaccines are distributed and used globally. 

– It was announced this week that  the vaccines are safe and effective in pregnant and lactating women.  There is no evidence that the vaccine affects current or future fertility.

I expect that there will be new developments on a regular basis at this point.  I’ll keep you updated. 

Be well.  Stay safe.

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