The physician and researcher in health policies and systems, Dr Tayeb Hamdi, addresses in an analysis all the scientific questions relating to this third dose.
Why a third dose?
Many countries had already started administering a third dose to the most vulnerable people (organ transplants, on dialysis, under certain anti-cancer treatments, etc.) to protect them against severe forms and death from COVID.
In recent weeks, this third dose concerns other more generalized categories: over 65 years and people with chronic diseases.
Four scientific facts justify the injection of this third dose:
-Medically and immunologically, we know that the elderly, carriers of chronic diseases weakening immunity, are less good responders to vaccinations in general compared to young people and not sick.
-With the emergence of variants, and mainly Delta, the vaccine efficacy decreases, even if fully vaccinated people still have very high protection against severe forms and death.
-Studies have shown that six months after vaccination, antibodies start to drop, although protection is not provided only by antibodies, but also cellular immunity.
-On the deaths observed because of COVID-19 since the start of the vaccination, the statistics conclude at 99.5% of deaths among the unvaccinated, and only 0.5% of people fully vaccinated.
This proves the very high protection of vaccination against severe forms and death. By analyzing these extremely rare deaths among the vaccinated, we find the very old and the carriers of chronic diseases weakening the immunity.
Who are eligible for this third dose?
The priorities are people over 65 and those with chronic diseases, given the risk of serious forms, and some countries already include groups at high risk due to increased exposure to the virus, such as health professionals, teachers, prison workers …
When to receive this third dose?
Six months after the first two doses and eligible people will be informed by SMS of 1717. What side effects?
A very recent study has shown that the side effects are not serious and similar to those observed during the second dose: pain at the injection site, headache, sometimes fever, etc.
Can this third dose be different from the other two?
The third dose can be the same type as the first two doses, as it may be different. Mixing of vaccines is not only possible, but desirable: compared to vaccination with the same vaccine, the production of antibodies is greater in the event of mixing.