Pfizer’s low-dose Covid-19 vaccine fails in children under five, experimental data shows

Photo of the article titled Pfizer & # 39;  s Low-Dose Covid-19 Vaccine Failed in Children Under Five, Experimental Data Shows

Photo: Thomas Kinzel / Agence France-Presse (Getty Images)

Today brought some frustrating news to parents in the United States who are hoping to soon vaccinate their young children against COVID-19. Based on clinical trial data, Pfizer and BioNTech announce He said Friday that children aged two to five years old did not produce an adequate immune response to two doses of the low-dose covid-19 vaccine, even though children aged 6 months to 2 years appeared to do so.

The companies are now planning to extend their trial by adding a third, lower dose to the schedule, for both this age group as well as children ages 5 to 12. You will have to wait until the first half of next year.

The combined Pfizer/BioNTech trial included more than 4,500 children aged six months to 11 years in the United States, Finland, Poland and Spain. Those over 5 mcg of the vaccine (one-third of the adult dose) were given in a two-dose schedule 21 days apart, while those under 5 were given a 3 mcg dose per injection.

In late October, the Food and Drug Administration authorized Pfizer/BioNTech vaccine for children 5 to 11 years old. The decision was based on data showing that the vaccine was about 90% effective in preventing coronavirus, as well as data showing that their immune response was similar to what has been seen in younger adults already. Unfortunately, this immune response was not as strong for the vaccinated children in the 2- to 4-year-old group, Pfizer/BioNTech reported Friday, based on a provisional analysis of the data.

Failure will inevitably delay any vaccination program for these age groups. Although children between the ages of six months and two years appear to have a robust immune response, the companies made a decision (with the blessing of the regulatory authorities) to adjust the study for all children under five. They will now receive a third dose of 3 micrograms at least two months after the second dose. The companies also announced that they plan to study a third dose of 10 mcg for children 5 to 11 years old, as well as for adolescents 12 to 17. If a third dose appears to be effective for younger children, the companies plan to file an emergency use authorization (EUA) application in half the first of 2022.

The decision to use lower doses for children was based on the hope that it would provide similar protection as adult doses, while reducing any potential side effects, particularly the increased but rare risk of developing heart inflammation (myocarditis) seen in adolescents and young adults, more in males than in females. So far, at least, there is did not There was no indication of major safety concerns in children ages 5 through 11. The CDC identified eight cases of myocarditis among this age group after vaccination, although it did not say whether these cases were related to the vaccines. All cases appeared to be mild and at least five cases recovered. According to the Center for Disease Control and Prevention.

But the latest findings suggest that it can be difficult to find a balance in the optimal dose and scheduling of a vaccine, for all age groups. In light of research showing that immunity has begun to wane for those vaccinated with two doses, as well as the emergence of variants such as Delta and now Omicron, many scientists and even health officials have I started To demand that mRNA vaccines be classified as a three-dose vaccine, not a two-dose. And that appears to be the direction Pfizer/BioNTech is heading.

In a conference call on Friday, The New York Times mentioned , Katherine Janssen, Pfizer’s head of vaccine research, explained that the company will seek to license its vaccines as a three-dose series for children. And if it does, it may pave the way for its application to all age groups.

Several studies have shown that people given three doses appear to have stronger protection against infection than Delta and possibly Omicron, although there is still a question as to how long this increase in immunity will last.

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