Mary Knudtson DNSc, NP, FAAN
There has been discussion of whether people with immunocompromising conditions should receive a 3rd dose of the mRNA COVID vaccine. The CDC presented at the Advisory Committee on Immunization Practices (ACIP) meeting on July 22, 2021 regarding the data they have.
As background information, about 2.7% of US adults are immunocompromised. For purposes of the presentation, immunocompromised is defined as:
Their data showed immunocompromised people are at higher risk of becoming severely ill from COVID-19 than the general population; higher risk for prolonged SARS-CoV-2 infection and shedding were also noted in immunocompromised people. In addition, this population is more likely to transmit SARS-CoV-2 to household contacts and to experience breakthrough infections.
Data on vaccine effectiveness (VE) of the mRNA vaccines in immunocompromised people was also presented:
All of the studies they presented showed a lower mRNA vaccine effectiveness for people with immunocompromising conditions than those without.
Lastly, they presented the emerging data on the evidence they have from giving a 3rd mRNA COVID-19 vaccine dose to immunosuppressed people. Notably, with a 3rd dose, 33% to 50% of immunocompromised people developed a seropositive antibody response; these patients had previously demonstrated no detectable antibody response to the initial 2-dose mRNA vaccine series.
France, the UK, and Israel are now already recommending or strongly considering a 3rd dose of mRNA vaccine for people with immunocompromising conditions. The emerging data from the CDC do seem to support this approach.