Since the first clinical trials, the question remained unanswered: in addition to preventing the symptomatic forms of Covid-19, would vaccines also prevent the spread of the coronavirus? In the United States, a study by the Center for Disease Control (CDC) provided some answers that seem to go in the right direction.
Four thousand people vaccinated with immunizers that use messenger RNA technology, such as those from Moderna or Pfizer / BioNTech, were followed up by a medical team in the United States. 14 days after the second dose, 90% of them were declared completely immune: the coronavirus was unable to pass through them.
Therefore, people immunized with this type of vaccine logically can no longer transmit it. The effect is also present after the injection of the first dose, although it is less: it affects about 80% of those vaccinated.
The implications of this discovery in terms of controlling the pandemic are very interesting: experts insist that it really changes a lot whether vaccinated people actually form a protective wall against the spread of the pandemic. The United States CDC therefore recommends opening vaccination for everyone.
Children and vaccines
Apart from the contingencies of stocks that have led health authorities in several countries to vaccinate the most vulnerable (older people or those with comorbidities), a part of the population remains completely excluded from the systems: children and adolescents. However, it can be seen that the virus continues to circulate actively among the little ones.
The reason is simple. Clinical trials did not involve minors under the age of 18. Without data, they are therefore currently excluded from vaccination campaigns.
However, that is about to change. Several clinical trials around the world have been launched to obtain the missing information and the first results are coming. Pfizer announced that its vaccine is 100% effective in adolescents aged 12 to 15 years in preventing symptomatic forms of Covid-19.
This is an impressive number that needs to be put into perspective, however. The study was carried out on about 2300 adolescents and concerns only the symptomatic forms. However, we know that this population usually declares asymptomatic forms of the disease. In parallel, therefore, it will be necessary to determine whether the effects on contamination will also be sufficient.
In addition, the Pfizer announcement was made once again through a press release. Therefore, we will have to wait for the publication of the complete data to have a more precise idea. However, this does not prevent the laboratory from wanting to send the results obtained to the North American and European health authorities to include the extension of these age groups in the authorization of its vaccine.
Covid-19 and flu
That was one of the concerns of this winter that has just taken its last breaths in the northern hemisphere: would the seasonal flu epidemic be added to that of Covid-19? In fact, influenza kills between 10,000 and 15,000 people every year in France and always disrupts resuscitation services at ICUs.
Good news, this was not the case this season. In fact, according to the report by the French Public Health Agency, published on Wednesday (31), no sick person with the flu has passed through the doors of one of the 226 intensive care units that monitor the epidemic since the month of October .
This result is probably due to vaccination at the same time in 2020, which was particularly effective, and to measures of social distance. It is now known that they work against Covid-19 and are equally effective against the flu. We have also seen its effect on other diseases, such as bronchiolitis and gastroenteritis, which are much less present this year.
Pfizer vaccine is effective against the South African variant
The Pfizer / BioNTech alliance said on Thursday (1) that their vaccine had a very high effectiveness against the South African variant of the coronavirus, citing findings from clinical trials conducted in South Africa.
No case of Covid-19 was seen in South Africa in people vaccinated during the phase 3 clinical trial, which tracked participants for up to six months after the second injection, according to an official statement from the company.
In this country, “800 participants were recruited, nine cases of Covid-19 were observed, all in the placebo group, which indicates a vaccine effectiveness of 100%”, explained the released document.
These are “the first clinical results that show that a vaccine can effectively protect against the variants currently in circulation, an essential factor in achieving group immunity and ending this pandemic for the world population”, explains Ugur Sahin, CEO and co- founder of BioNTech.
* With information from AFP
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