COVID-19: Pfizer to test third dose of vaccine for children below 5 yrs amid Omicron scare

Pfizer and BioNTech on Friday shared that they are following a "routine review" to administer the third dose of COVID-19 vaccines on children below 5 years to evaluate the safety, tolerability and immunogenicity. The pharmaceutical company will now test the third dose of 3 µg at least two months after the second dose of the two-dose series to provide high levels of protection in this young age group, Pfizer said in a statement. The change in the trial protocol, however, means that the companies will not be able to submit data on the impact of vaccines on young kids by the end of 2022, which was promised by Pfizer CEO Albert Bourla earlier this month.

It is pertinent to mention that news came after Pfizer and BioNTech discovered a lack of robust immune response in some children after the two-dose regimen. In the statement released on Friday, it clarified that while the vaccine efficacy was adequate among kids under 2 years, compared to those seen in the trial of 16-25 year-olds, but the cohort of 2 to under 5 did not produce the expected results. Although, no safety concerns were identified and 3 µg demonstrated a "favourable" safety profile in children between 6 months to under 5-years-old.

Speaking to investors during a press conference, Pfizer head of vaccine research, Kathrin Jansen highlighted that the data on variants also included a study of vaccine effectiveness against Omicron. She informed that individuals with three doses displayed a higher degree of immunity than those jabbed with two doses. "Therefore, we have decided to modify each of the pediatric studies to incorporate a third dose to the series and seek licensure for a three-dose series rather than a two-dose series as originally anticipated," Jansen said, as quoted by NBC broadcaster.

Pfizer-BioNtech to evaluate 10µg booster on children aged 5-11

As per the press release on Friday, Pfizer and BioNTech informed that an ongoing study for kids aged 6months to under 5-yeats will now be inoculated with 3µg of mRNA given at least 2 months after the two-dose regimen. The experts will continue testing 3µg for the same age group but increase to 10µg for kids aged 5-11. In case trials are successful, the company is expected to report the findings to drug regulators for emergency use authorisation (EUA) of three-dose series for all children aged 6 months to under 5-years in the first half of 2022.

So far, Food and Drug Administration (FDA) has authorised only emergency use or Pfizer-BioNTech vaccine in children aged 5-years and older. Last month, the FDA endorsed the third booster dose for Pfizer-BioNTech and Moderna vaccines for all US adults. The developments come amid skyrocketing cases of the COVID-19 Delta variant, coinciding with the new variant Omicron, which has been dubbed "Variant of Concern" by the World Health Organisation.

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