“A single dose” of vaccine against Covid-19 is enough for patients who have already had the disease, recommended Friday the French health authorities, a measure that would save a large number of doses in a context of constrained supply .
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These people “have already developed (…) an immune memory. The single dose of vaccine will thus play a reminder role, ”explains the High Authority for Health in its opinion, which has yet to receive government approval.
The authority recommends to wait “beyond three months” after the disease, “and preferably six months”, before injecting this single dose.
“To date, no country has clearly positioned itself on a one-dose vaccination for people who contracted COVID-19 prior to the vaccination,” underlines the HAS.
The experts behind this recommendation even considered the possibility of not vaccinating former patients at all, considering that “like other infections such as measles, such as chickenpox, there is an immunity that is set. in place ”, which“ will make it possible to protect over a very long period of time, ”explained infectious disease specialist Olivier Epaulard, during an online press briefing.
“But given that we lack perspective and that, moreover, we have vaccines, we preferred to say that we were going to vaccinate these people anyway,” he added.
“Doses saved”
The authorities are relying heavily on the vaccination campaign to cope with an epidemic situation which remains fragile, but the road is still long: Thursday, 2,135,333 people had received at least one dose of vaccine, including 535,775 two doses.
The government’s objectives in terms of people vaccinated have been disrupted in particular by the announcements of deliveries lower than forecasts from the British laboratory AstraZeneca.
The three COVID-19 vaccines currently authorized in the European Union (Pfizer / BioNTech, Moderna and AstraZeneca / Oxford) require two doses to be fully effective in people who have never been in contact with the virus.
That of Johnson & Johnson, currently under review by the European Medicines Agency, however requires a single injection.
Since the start of the COVID-19 pandemic, 3.4 million cases of infections confirmed by a screening test have been recorded in France.
The people concerned “are not all priority for vaccination but (…) that makes so many doses saved”, underlined the president of the HAS, Dominique Le Guludec.
More people have likely contracted the virus, especially during the first wave, when testing was not widely available.
In this case, the HAS recommends administering the two doses and not to carry out an express serological test demonstrating or not the presence of antibodies.
Logistics
The recommendation for a single dose of vaccine also does not apply to immunocompromised people, for example transplant recipients who are undergoing immunosuppressive therapy.
“The presence of persistent symptoms after COVID-19 is not a contraindication to vaccination. However, in this case, an appropriate medical consultation is necessary “to” judge on a case-by-case basis the interest “to be vaccinated, adds the HAS.
The government generally follows the advice of this body. At the end of January, however, he had chosen not to increase the time between the two doses of Pfizer vaccine, contrary to the recommendation issued a few days earlier by the HAS.
The authority bases its opinion in particular on the analysis of scientific studies concerning the immune response of people cured of COVID-19 and their tolerance to vaccines.
In recent days, several studies carried out in the United States and Italy, not yet evaluated by other scientists, evoked this solution of a single dose for ex-patients of COVID.
“In individuals with pre-existing immunity, the antibody response to the first dose is equivalent or even greater than that detected after the second dose” in people who have never been infected with the coronavirus, writes one of these teams, based at the Icahn School of Medicine in New York.
“Implementing this as part of a mass vaccination program could be logistically complex”, however qualified Eleanor Riley, infectious disease specialist at the University of Edinburgh, quoted by the British organization Science Media Center .