Like all trials, there are limitations. As mentioned, the number of infections here is small—the impressive efficacy numbers could potentially vanish in a larger trial with more infections. And, while the trial had a high-quality design, it was undertaken in just one location in Germany and mostly involved healthy white women between the ages of 20 and 46, so the findings are not generalizable. The study was also funded by a pharmaceutical company that makes an azelastine nasal spray (though not the one that is sold over the counter in the US).

Still, with the previous studies, the trial offers some hope that this accessible nasal spray could be used as a viral prophylactic for respiratory seasons in the future. And the results land at a time when access to COVID-19 vaccines—which have firmly proven to be safe and highly effective—has been severely restricted in the US by health secretary and anti-vaccine activist Robert F. Kennedy Jr.

As it stands now, it appears that only people ages 65 and over, and those at higher risk of COVID-19 will have access to the shots this year, though some aspects of that access are murky, including how people will prove they're at high risk. For healthy children, teens, and adults under 65, there may be no access or extremely limited access. That includes groups that medical experts recommend get vaccinated, namely healthy pregnant people and children ages 6 months to 23 months, both of which are considered at high risk from COVID-19 by medical experts, but not federal guidance under Kennedy. Experts also recommend access for healthy people who have contact with vulnerable people, such as cancer doctors, people who live with immunocompromised family members, and people who work in nursing homes.

With limited vaccine access and the normal slew of respiratory viruses on the horizon, a simple nasal spray is an appealing addition to the defenses. The main side effects are fairly minor, including bitter taste in the mouth, nosebleeds, and tiredness.