BNT162b2 vaccine highly effective against severe COVID-19 in teens

The BNT162b2 mRNA vaccine proves to be highly effective against COVID-19 hospitalization and critical illness in adolescents aged 12 to 18 years, including those with pre-existing comorbidities, according to real-world data from the Overcoming COVID-19 surveillance network sponsored by the US CDC.

“Vaccination averted nearly all life-threatening COVID-19 illness in this age group,” the researchers highlighted.

Overall, the BNT162b2 vaccine was 94 percent effective against COVID-19 hospitalization (95 percent confidence interval [CI], 90–96). [N Engl J Med 2022;386:713-723]

Among patients who developed severe COVID-19, unvaccinated patients accounted for 45 percent of the severe cases while those fully/partially vaccinated made up only 11 percent of the cases. 

The vaccine was 98 percent effective against ICU admission, as was against the need for life support. For ICU admission, 42 percent of the cases were made up of unvaccinated patients compared with 11 percent of fully/partially vaccinated patients. Similarly, fivefold more unvaccinated patients required life support than those who had been fully/partially vaccinated (30 percent vs 6 percent).

There were seven deaths, all of which occurred in unvaccinated patients.

“Despite eligibility for COVID-19 vaccination, 96 percent of the patients who were hospitalized with COVID-19 and 99 percent of those who received life support had not been fully vaccinated,” the researchers noted.

Added evidence from real world

In the real-world study with a case-control, test-negative design, 445 case patients hospitalized for COVID-19 were compared against 777 hospital-based controls who showed COVID-19–like symptoms but tested negative (test-negative controls) or those without COVID-19–like symptoms (syndrome-negative controls).

When the analysis was stratified based on the control groups, vaccine effectiveness against COVID-19 hospitalization was 95 percent (95 percent CI, 91–97) compared with the test-negative control group and 94 percent (95 percent CI, 89–96) compared with the syndrome-negative controls.

While a recent clinical trial has shown high efficacy of the BNT162b2 vaccine in protecting against nonhospitalized COVID-19 illness in adolescents, the rate of COVID-19 hospitalizations in that study was too low to draw any conclusion on its efficacy against severe illness. [N Engl J Med 2021;385:239-250]

Also, vaccine effectiveness may differ in adolescents with pre-existing risk factors for severe illness — a group commonly present in hospitalized settings but often excluded from clinical trials, the researchers pointed out. Unlike the previous study, a large proportion of the case patients (74 percent) in the current real-world study had underlying conditions (including obesity).

“[Despite] the high prevalence of underlying medical conditions in our study cohort, we observed that vaccination was associated with an overall risk reduction of 94 percent for COVID-19 hospitalization and 98 percent for ICU admission or life-threatening COVID-19 illness,” the researchers reported.

‘Distressing’ vaccination rate

“These extremely encouraging data indicate that nearly all hospitalizations and deaths in this population could have been prevented by vaccination,” wrote Dr Kathryn Edwards from Vanderbilt University Medical Center, Nashville, Tennessee, US, in a linked editorial. [N Engl J Med 2022;386:789-790]

“However, it is distressing that less than 39 percent of the adolescents in the control group had been immunized against COVID-19, despite uniform eligibility and widespread vaccine access,” she stated.

These immunization rates, according to her, stand in stark contrast to the rates for routine paediatric vaccinations, which usually sit above 95 percent.

“Vigorous efforts must be expended to improve vaccination coverage among all children and especially among those at highest risk for severe COVID-19,” she urged.