On Tuesday, Eli Lilly & Co. said that enrollment in a government-sponsored clinical trial of its antibody therapy had been paused out of safety concerns. That came less than 24 hours after Johnson & Johnson said research on its experimental vaccine was paused after a study volunteer fell ill.

The developments are likely to heighten worry that the pursuit of products to prevent and treat infections is moving too quickly. Regulators and drugmakers have faced questions about whether political pressure was overwhelming scientific rigor ahead of the presidential election on Nov. 3. Last week, President Donald Trump, trailing in the polls, touted antibody treatments as a cure, and his administration has pushed hard for the rapid approval of the treatments and a vaccine.

However, the trial complications are happening in an environment of intense scrutiny, executives and industry observers said, and the highly public nature of the hunt for vaccines and treatments is magnifying events that in other studies would be considered routine.

“I’m not surprised at all that these pauses are happening. Where I would be surprised is if they weren’t happening,” said Greg Poland, director of the Vaccine Research Group at the Mayo Clinic in Rochester, Minnesota.