The CDC’s Advisory Committee on Immunization (ACIP) has unanimously recommended that certain categories of people with moderate or severe immunodeficiency receive a third dose of RNA (mRNA) of the COVID-19 vaccine.
The categories of people who are recommended to be vaccinated with a third dose of RNA (mRNA) of the COVID-19 vaccine:
persons who are in the process of treatment or have recently been treated with hematologic malignant tumors;
individuals who have recently undergone a solid organ transplant or a recent blood stem cell transplant;
persons with severe primary immunodeficiency disorder;
people with progressive HIV infection and PLHIV who do not take ART;
people with chronic diseases such as asplenia (absence of a spleen) or chronic kidney disease.
people taking high doses of corticosteroids, antimetabolites, tumor necrosis factor blockers and other biologics that suppress or modulate the immune system.
Why the third dose?
According to reports made at the ACIP meeting, people with moderate to severe immunodeficiency are especially vulnerable to infection with COVID-19 and tend to have a decreased immune response to the first two doses of vaccination.
With the recent rapid rise in hospitalizations and deaths due to the spread of the Delta strain, some cases of hospitalizations still occur in people with immunodeficiency conditions. Even if they have not been hospitalized, they are often more likely to become seriously ill and have a long period of illness.
The reason? In persons with immunodeficiency, the formation of a lower antibody titer and neutralization to SARS-CoV-2 is observed than in healthy immunocompetent people.
In general, the effectiveness of vaccination with two doses of mRNA vaccine for immunocompromised people ranges from 59% to 72%, while for people with healthy immune systems, the effectiveness of the vaccine ranges from 90% to 94%.
Although the third dose of vaccine in people with immunodeficiency is equivalent to the protection that a person with a healthy immune system receives, 33% – 50% of people have developed a strong immune response to the additional dose.
The experts noted that it is important for people with immunodeficiency to continue to adhere to the necessary preventive measures because even after the third dose, their immune response will still be less than that of other people. Such preventive measures include wearing masks, social distancing and crowd avoidance, especially in poorly ventilated areas.
The ACIP and the FDA also recommend that physicians strongly encourage vaccinations in the immediate environment of immunocompromised people to increase their protection against possible infection.
Olga Bula