COVID-vaccine results are on the way — and scientists’ concerns are growing

COVID-vaccine results are on the way — and scientists’ concerns are growing

Vaccine results: what to watch out for

Several ongoing coronavirus-vaccine trials — from Moderna, Pfizer and the University of Oxford–AstraZeneca — could announce game-changing results next month. Here are the areas that scientists are watching closely:

• Whether the vaccines will clear safety trials.
• What efficacy is achieved: makers are aiming for the vaccines to stop at least 50% of vaccinated people from getting symptomatic COVID-19, but are hoping for an efficacy of 60% or greater.
• Whether any vaccine will reduce severe disease and death. Study protocols revealed that the trials are designed to test whether the vaccines reduce cases of symptomatic COVID-19, not cases of severe disease.
• The level of transparency about any adverse effects experienced by trial participants. The Oxford–AstraZeneca trials remain paused in the United States over safety concerns, but have restarted in other countries and details have been thin. Scientists say openness is essential to maintain public trust.
• Fears that political meddling could see a vaccine approved for emergency use without sufficient evidence that it works. Especially in the United States, where the process has become part of intense political debate in advance of the impending presidential election.
• Whether trials will be allowed to run long enough to collect long-term safety data. Convincing preliminary results could end trials early.

Nature | 9 min read