Two doses of Covid-19 vaccine are not enough to develop antibodies in recipients of organ transplants like heart and kidney, patients of chronic immunosuppression and auto-immune disorders, according to experts. They have called for a need on giving a booster dose to them to enhance their immunity against the virus.
However, the government, which is already grappling with shortage of vaccine for general population, is yet to consider the emerging demand and frame a guideline in this regard. If that happens, the changes in the COWIN portal will have to be made as presently, it does not allow slot facility for the third booster. It has slots for only two doses.
Dr Rahul Bhargava, Director-Bone Marrow Transplant Program, Fortis Memorial Research Institute, Gurgaon, makes a case for the third booster for such patients “as they don’t respond very well to the vaccines because their immune system is suppressed”.
In fact, there are now studies that are suggesting, at least in organ transplants, if they get a third dose, their system may be triggered to produce protective antibodies, Dr Bhargava said adding that it’s high time the Government issue an advisory and subsequently update the COWIN portal to allow such patients, who have taken two doses of vaccines, to avail booster shot.
A recent study published this week in the ‘Annals of Internal Medicine’ has shown that nearly half of organ transplant recipients failed to show any antibody response even after two doses of the Pfizer or Moderna vaccine.
And even in transplant recipients who showed an antibody response to vaccination, that response was often more muted than in people with healthy immune systems, said researchers from Johns Hopkins School of Medicine who tracked 30 organ transplant recipients who got a third dose of Covid-19 vaccines.
They found that one-third of the patients who previously had no detectable antibodies showed an increase in their antibody levels after a third dose.
And all of the patients who previously showed low levels of antibodies after two vaccine doses showed high levels of antibodies after their third dose.
“So for all involved, [these are] encouraging findings that we might be able to ultimately really reach protective immunity in immunosuppressed people,” said Dr Dorry Segev, a transplant surgeon at Johns Hopkins Medicine and an author of the study.
Similarly, yet another report published in The New England Journal of Medicine said that a weak response to two doses of vaccine against Covid-19 has been observed in recipients of organ transplant. However, administration of a third dose of the mRNA vaccine BNT162b2 (Pfizer-BioNtech) to solid-organ transplant recipients significantly improved the immunogenicity of the vaccine, with no cases of Covid-19 reported in any of the patients.
The researchers said if the findings are replicated in larger studies, they may have implications for some other types of immunocompromised patients.
In fact, in France, health officials already recommend that severely immunocompromised patients, including organ transplant patients, dialysis patients, and others, receive a third dose of the Pfizer or Moderna vaccine.