The effect, according to some experts, has been a stifling of the scientific debate that risks impeding — rather than facilitating — progress, and the extension of the polarized political climate into the realm of public health. “One of the things I haven't liked is people kind of shouting at each other over face masks or airborne particles; or whether immunity wanes, or doesn't; or whether we should vaccinate children,” said Fiona Fox, director of the U.K.-based Science Media Centre, which helps connect journalists to credible experts.