The announcements also mean that the world will likely have more than one highly effective vaccine for Covid-19, and the end of the pandemic could be on the horizon. High efficacy also means that fewer people would need to be vaccinated in order to achieve herd immunity, the threshold at which the virus can no longer spread easily from person to person.
However, there are some caveats: The results are preliminary, the vaccine requires two doses, there are some side effects, the clinical trial isn’t complete, and the findings were announced in a
press release instead of a peer-reviewed paper. Moderna did not respond to requests for comment.
And while demonstrating high efficacy is important, the road to getting millions of people vaccinated is fraught with logistical challenges. While this is an important result, a lot of difficult work on a Covid-19 vaccine still lies ahead.