Story perspectives

Pfizer and BioNTech Halt COVID Vaccine Trial Due to Low Enrollment

4/2/2026

Summary

Story summary

Pfizer Inc. and BioNTech SE halted a U.S. trial for their updated COVID-19 vaccine aimed at healthy adults aged 50 to 64 after low enrollment.
The companies informed the U.S. Food and Drug Administration of the decision.
Strict health criteria hinder recruitment, with over 80% of potential participants failing pre-screening.
Moderna, Inc. is continuing a similar trial and faces its own recruitment difficulties.
Demand for COVID vaccines has declined, with only 18% of Americans receiving a booster during the 2025-26 season, despite ongoing COVID-related deaths in this age group.

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Story summary

Pfizer Inc. and BioNTech SE halted a U.S. trial for their updated COVID-19 vaccine aimed at healthy adults aged 50 to 64 after low enrollment.
The companies informed the U.S. Food and Drug Administration of the decision.
Strict health criteria hinder recruitment, with over 80% of potential participants failing pre-screening.
Moderna, Inc. is continuing a similar trial and faces its own recruitment difficulties.
Demand for COVID vaccines has declined, with only 18% of Americans receiving a booster during the 2025-26 season, despite ongoing COVID-related deaths in this age group.