Covid: A Third Dose of Vaccine to be Combined with that Against the Flu

The France  High Authority for Health recommended on Tuesday to administer a booster dose to already vaccinated people aged at least 65 years and to patients at risk, as wished by the government. He suggests injecting the flu shot at the same time.
A booster dose “for people 65 years of age and over, as well as for all people with co-morbidities that increase the risk” linked to Covid. The High Authority for Health (HAS) gave the government the green light on Tuesday to launch the “third dose” campaign in September, as the Minister of Health, Olivier Veran had hoped.

These are in fact vulnerable groups already a priority for the vaccine against seasonal influenza. The HAS proposes, “to avoid any delay in influenza vaccination and simplify the vaccination course”, to inject the two vaccines at the same time.

A period of at least six months
However, a period of at least six months must be observed between the end of the complete vaccination schedule and the administration of the “third dose” (which for some vaccinees is in fact a second or a fourth dose).

The government still evoked last week a recall for the more than 80 years. But the Director General of Health, Jerome Salomon, asked the High Authority to take into consideration those over 60 or 65, the chronically ill, health professionals and all those who did not have access to a vaccine. Messenger RNA.

HAS believes that there is no need to extend the recall campaign to other audiences at this stage, especially as vaccines remain very effective against severe forms. But she still recommends that a booster dose with a messenger RNA vaccine be given to anyone who has been vaccinated with Janssen, a single-dose vaccine regimen that has not been shown to be effective in the long term.

Before launching operations, and even if “it seems very likely that a booster injection 6 to 12 months after a complete primary vaccination will indeed provide a boost effect”, it will be necessary to wait for the European Medicines Agency to assess precisely The “tolerance” and “impact” of this recall.

More affected populations
In support of its proposal, the HAS cites several studies which “suggest a decrease in the efficacy over time of all vaccines, in particular against the Delta variant”. “This decline does not only affect the elderly and populations at risk of severe forms, but the latter remain the most affected,” he underlines.

Out of 622 serious vaccine failures identified by pharmacovigilance on August 13 following BioNTech / Pfizer injections, two-thirds concern people who suffered from one or more comorbidities. Of 107 deaths, 72% occurred in people aged 85 or older.

On the other hand, the decline in immunity over the months has not yet been demonstrated in France, explains the HAS: “Less than 5% of vaccine failures are reported after five months or more after vaccination, thus suggesting that To date, vaccine failures mainly concern people who have not responded well to vaccination and not people who have lost their protection over time ”.

Delta is changing the game
However, the surveyed sample still gives pride of place to the Alpha (“British”) variant, which has since been scanned by the Delta variant (found in only 17% of cases).

However, it is the Delta variant which changes the situation, writes the HAS, stressing that “the least protection concerns essentially the efficacy against infection and against the symptomatic forms, the efficacy against the severe forms remaining at a high level. , regardless of the vaccine administered ”.

With the Delta variant, as the US health authorities have shown, the viral load of vaccinated hospitalized patients is similar to that of the unvaccinated, although it drops more rapidly, “reflecting a probable lower transmissibility”.

Less effective against symptomatic forms
The HAS also mentions the data being updated from the Comcor study (Institut Pasteur, CNAM, Ipsos, SPF), which had shown an efficacy of 88% against the symptomatic forms due to the original strain of the virus, 86% with Alpha, and 77% with Beta. For the Delta variant, in June-July, the efficacy drops to 69% regardless of the messenger RNA vaccine (and to 66% in the case of an AstraZeneca + Pfizer or Moderna combination).

Finally, she cites several Israeli studies tending to show a decrease in protection against infection, “a significant decline in immunity over time and less efficacy against the Delta variant”. But these data “need to be confirmed”, underlines the HAS, because there is a lack of hindsight and observations in the field are parasitized by a multitude of factors.

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