Understanding the need for antibody titer and issues among immunocompromised patients
This week, we shift our focus on the need to measure the antibody and whether or not this is important.
First, we need to know what is meant by antibody titer.
An antibody titer is a laboratory test that measures the level of antibody in a blood sample.
Antibody titer determination and vaccination challenges are among the issues in immunocompromised patients.
In the foregoing, here are some facts to consider:
- The Food and Drug Administration (FDA) does not advise using antibody titer in post-vaccination as there are other immune cells activated after vaccination. This includes the T and B cells. The T cells are responsible for cell-mediated immunity that does not involve antibodies, instead it leads to the production of cytokines which are directed against the virus; while B cells are responsible for antibody production when activated by the vaccine.
- Robust T- cell immune responses after vaccination, which are not subjected to antibody measurement, provide protection especially against severe disease, regardless of antibody level. Thus antibody titer alone is not the only measure of immunity
- Since we don’t have the scientific data to the clinical significance of antibody titer determination, routine titer determination is not recommended as it may create false sense of security or false sense of vulnerability if titer result shows low antibody count.
- Due to paucity of data, immunosuppressed patients such as those suffering from cancer and are on chemotherapy, those who have undergone organ transplant, etc., should only receive booster dose under emergency use authorization. Research to address booster dose among healthy individuals is ongoing.
- In this connection, it is suggested that all immunocompromised patients be vaccinated, but should not rely only on this intervention to keep them safe. They should continue to wear mask and maintain minimum health protocols. Similarly, their close contacts should also be encouraged to get the vaccine in order to reduce the risk of transmission.
- Vaccination on an immunocompromised patient should be done at a time of reduced immunosupression like giving the vaccine before solid organ transplantation, between chemotherapy cycles and for a stable patient, it is advisable to hold some immunosuppressive therapy for 1-2 weeks after giving the vaccine.
In the meantime, we have to remind everyone that all Coved-19 vaccines decrease the risk of a severe disease by 90% against all covid19 variant, including the scariest Delta variaant.