CDC trial finds Comirnaty highly protective in adolescents

Results from a US Centers for Disease Control and Prevention (CDC) study released Tuesday showed that Pfizer and BioNTech's COVID-19 vaccine Comirnaty was 93% effective at preventing hospitalisations among those aged 12 to 18 years old. The findings "reinforce the importance of vaccination to protect US youths against severe COVID-19," CDC researchers wrote in their Morbidity and Mortality Weekly Report.

The vaccine, also known as BNT162b2, was first granted an emergency-use authorisation (EUA) late last year for people 16 and older, and recently secured full approval in this group. The EUA was extended in May to allow it to be administered to children as young as 12.

The CDC study was conducted between June and September, when the contagious Delta variant was predominant. The final analysis comprised 179 case-patients, among whom only six were vaccinated. Participants had a median age of 15 years, and nearly three-quarters had at least one underlying condition, including obesity.

ICU cases, deaths among unvaccinated

Overall, 77 case-patients, or 43%, were admitted to an intensive-care unit (ICU), with 29 of them characterised as being critically ill and requiring life support. There were two deaths among the group. The CDC said none of the 77 patients had been vaccinated.

Discharge information was available for 169 case-patients, showing that hospital stays lasted five days on average for those who were unvaccinated, compared to stays of three days for vaccinated case-patients. Further, the agency noted that vaccine efficacy was similar for younger and older teens; at 91% among those ranging in age from 12 to 15, and 94% for those between 16 and 18.

CDC scientists cautioned that the study was limited by its small sample size, which prevented them from properly measuring vaccine effectiveness in patients with underlying conditions. They also could not determine the vaccine's ability to protect against specific coronavirus variants, and noted that some participants may have misrepresented their self-reported vaccination status.

Follows safety concern holding up Moderna review

According to the agency, 46% of US children and adolescents aged 12 to 15 years and 54% of those aged 16 to 17 years were fully vaccinated against COVID-19 as of October 18. Pfizer and BioNTech recently filed for FDA authorisation to extend the vaccine's use to children ages five to 11 years old.

Last week, the FDA delayed its review of Moderna's request to allow its vaccine mRNA-1273 to be use in children 12 through 17 as the agency looks into the potential risk of a rare inflammatory heart condition. The vaccine has been authorised in the EU under the name Spikevax for people as young as 12 since July. Meanwhile, Johnson & Johnson earlier this year expanded a Phase II trial to include testing its coronavirus vaccine Ad26.COV2.S in young people 12 to 17 years of age.  

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