Immunocompromised patients should have third COVID-19 vaccine
Thursday March 3rd 2022
Immunocompromised patients, particularly those who have had organ transplants, should receive additional COVID-19 vaccines, experts recommend today.
The findings, published in the latest edition of The BMJ, reinforce the importance of additional doses of COVID-19 vaccine to protect people with a weakened immune system.
Although it is known that immunocompromised people are less able to make antibodies after vaccination to fight off viruses, such as influenza, than those who are immunocompetent, less is known about the response to COVID-19 vaccines, particularly mRNA vaccines.
Researchers in Singapore analysed the results of 82 observational studies, to compare the effectiveness of COVID-19 vaccines in immunocompromised and immunocompetent people.
Of these studies, 77 (94%) used mRNA vaccines, 16 (20%) viral vector vaccines, and 4 (5%) inactivated whole virus vaccines. A total of 63 studies were assessed to be at low risk of bias and 19 at moderate risk of bias.
After one COVID-19 vaccine dose, seroconversion was found to be reduced among immunocompromised groups, except people with HIV.
Seroconversion rates were about half as likely in patients with blood cancers, immune mediated inflammatory disorders such as rheumatoid arthritis and psoriasis and solid cancers compared with immunocompetent controls. Organ transplant recipients were 16 times less likely to seroconvert.
A second dose significantly increased seroconversion in patients with blood cancers, immune mediated inflammatory disorders and solid cancers. However, only one third of transplant patients achieved seroconversion.
A further review of 11 studies showed that a third dose of a COVID-19 mRNA vaccine was associated with seroconversion among vaccine non-responders with solid cancers, blood cancers, and immune mediated inflammatory disorders. However, results showed a varied response in transplant recipients. No published evidence was available for people with HIV.
Although the included studies were observational and used different definitions of seroconversion, the research team said stringent study inclusion criteria, as well as rigorous and systematic evaluation of study quality, mean their conclusions are robust.
Lee Yan Bin AR, Wong SY, Chai LYA et al. Efficacy of COVID-19 vaccines in immunocompromised patients: systematic review and meta-analysis. BMJ 3 March 2022
Tags: Asia | Flu & Viruses | Pharmaceuticals | World Health
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