National Expert Committee on Immunoprophylaxis discusses need for revaccination against COVID-19

The National Expert Committee on Immunoprophylaxis, which met on 24 August, discussed issues related to COVID-19 vaccination, including the need for possible future booster doses. Experts believe that the focus should continue to be on vaccinating people who have not yet been vaccinated in order to prevent severe cases of COVID-19 and thus the overburdening of the healthcare system. The Expert Committee does not yet consider booster doses or revaccination necessary; however, additional data on admission rates, cases of COVID-19 in vaccinated individuals and the effects of a third vaccine dose are constantly being reviewed.

"The Expert Committee agreed that we must now focus first and foremost on vaccinating people who have not yet been vaccinated, especially the elderly. These are the people who are most likely to become seriously ill and be hospitalised. Unvaccinated people are four times more likely to become infected and 8-10 times more likely to be hospitalised than fully vaccinated people," said Prof Irja Lutsar, member of the National Expert Committee on Immunoprophylaxis. "According to the Expert Committee, we do not have enough scientific data to start with booster doses. We see that COVID-19 vaccines continue to be highly effective (90 percent and more) in preventing severe illness. The Expert Committee will meet to discuss the topic again in the second half of September after the publication of additional scientific data and a more thorough analysis of Estonia's own data."

The Ministry of Social Affairs has described four possible revaccination scenarios. The likely scenarios are that all people who have been vaccinated will need to be revaccinated 12 months after being fully vaccinated, a limited group of people will need an additional dose depending on whether the immune response is maintained or all people vaccinated with a particular vaccine will need an additional dose.

For the so-called third doses, the Committee recommends distinguishing between additional and booster doses. Additional doses are required to complete the vaccination course in people with severe immunodeficiency who do not develop adequate protection after receiving two doses (or one dose in the case of the Janssen vaccine), such as people with organ transplants or cancer patients who are receiving immunosuppressive therapy. A booster dose may be needed by all people who have been fully vaccinated after a certain period of time due to a weakened immune response.

The Expert Committee considers it important to continue preparations to start with both additional and booster doses.A recommendation for additional doses in immunocompromised individuals can be made after further scientific data becomes available in September. There is not yet enough scientific data to start with booster doses in the general population. Furthermore, the European Medicines Agency has not yet started the EU marketing authorisation application process for the booster dose of any vaccine manufacturer.

In addition, the Expert Committee discussed contraindications to COVID-19 vaccination. A contraindication to the administration of a vaccine is hypersensitivity to the active substance or to any of the excipients. In addition, Janssen and AstraZeneca COVID-19 vaccines are contraindicated in people with a history of capillary leak syndrome.

The National Expert Committee on Immunoprophylaxis is a committee advising the Ministry of Social Affairs on the national immunisation plan and other vaccination-related matters. The Committee is composed of representatives of immunologists, allergists, infectious disease specialists, family physicians, paediatricians, nurses, the Health Board, the Health Insurance Fund and the Ministry of Social Affairs.

The objectives of COVID-19 vaccination are to reduce COVID-19-related illnesses and deaths, to protect at-risk groups who have a higher risk of developing severe illness from COVID-19, to reduce the spread of coronavirus in Estonia and thus control the third wave of COVID-19 as much as possible, to reduce the burden on the healthcare system and the economy and to keep Estonian society as open as possible. To find out more about vaccination, visit www.vaktsineeri.ee or call the national helpline 1247.