Vaccines

People with significant T cell deficiencies, such as severe combined immunodeficiency (SCID) or congenital athymia, should not get any vaccines until they have been treated with hematopoietic stem cell transplantation (HSCT), gene therapy, or thymus implantation and have been cleared to receive vaccines. It is particularly important that they do not receive any live, attenuated vaccines. Live vaccines could actually cause the disease they are supposed to prevent in people with very low T cells. Newborn babies are at the greatest risk because live, attenuated vaccines like rotavirus and BCG (outside the U.S.) are given within the first few weeks after birth.

People with mild or partial T cell deficiencies, such as DOCK8 deficiency or Down syndrome, should get all nonviable vaccines. However, they may not develop enough protection from nonviable vaccines to be fully protected. Depending on how low a person’s T cells are, the person may also be able to receive some live, attenuated vaccines, like the chickenpox and measles-mumps-rubella (MMR) vaccines. Caregivers and primary care providers should discuss with an immunologist whether it is safe to give live, attenuated vaccines to a person with mild T cell deficiency prior to giving the vaccine(s).

Children and adults with significant antibody deficiencies, such as X-linked agammaglobulinemia (XLA) or common variable immune deficiency (CVID), generally cannot make antibodies in response to vaccines. It is safe to give people with significant antibody deficiencies nonviable vaccines, but these vaccines may not be helpful. For this reason, some immunologists do not recommend routine vaccination for people with significant antibody deficiencies, as long as they are on immunoglobulin (Ig) replacement therapy. Ig replacement therapy provides protective antibodies from other people against vaccine-preventable diseases, such as chickenpox and tetanus. It should also be noted that the antibodies in Ig replacement therapy can reduce the effectiveness of live vaccines.

However, Ig therapy does not provide enough protection against some infections, like COVID-19, influenza, and whooping cough (pertussis). Because the COVID-19 and influenza viruses change rapidly, the donated plasma used to make Ig may not have enough antibodies to the most current version of the viruses to protect people on Ig replacement therapy. This is because it takes time to collect plasma and produce a batch of Ig. That's why many immunologists recommend that people receiving Ig replacement therapy get seasonal nonviable vaccines each year.

In addition, people with significant antibody deficiencies may get some benefit from nonviable vaccines that stimulate T cell immunity, such as inactive influenza [11], even if they do not make antibodies [12].

Since most people with significant antibody deficiencies are on Ig replacement therapy, and live attenuated vaccines are not given to people receiving Ig therapy, the majority of people with significant antibody deficiencies do not receive live, attenuated vaccines.

For milder antibody deficiencies, such as selective IgA deficiency or specific antibody deficiency (SAD), all vaccines can usually be given safely, although some may be less effective. Children and adults who struggle to produce antibodies to polysaccharide vaccines (e.g., Pneumovax 23), like those with SAD, should receive the matching protein-conjugated vaccines (e.g., Prevnar 21) if they are available. Most patients with mild antibody deficiency can safely receive all live, attenuated vaccines. 

The third group includes people with disorders affecting their phagocytes, which are white blood cells that eat and destroy germs. Examples include CGD and leukocyte adhesion deficiency (LAD).

People with these conditions can safely receive nonviable vaccines. However, they should not receive vaccines that contain live bacteria, such as the BCG vaccine (not usually given in the U.S.). Whether or not to get vaccines with live viruses depends on the specific disorder. For example, people with CGD should get live virus vaccines, but some of these vaccines might not be safe for people with LAD.

The fourth category includes people with complement deficiencies. They should receive nonviable vaccines and may need boosters more often than usual (every 3-5 years) [8], [13], [14]. Most live vaccines can be given safely to people with complement deficiencies [13].

The last group includes people with other innate immune disorders, such as interferon gamma disorders and natural killer (NK) cell deficiency. These people can safely receive nonviable vaccines, but they may not work well in some cases. The safety and effectiveness of live, attenuated vaccines depends on the specific PI and must be considered for each person individually.