Vaccines Fight Covid, But Can They Stop the Spread?
Trials that show vaccines prevent Covid-19 symptoms haven’t established whether they also prevent transmission of the virus. That’s a problem.
Vaccine euphoria ignores a major unknown that can slow our return to normal.
Photographer: Mark Kauzlarich/BloombergCovid-19 vaccines, now closer to becoming widely available than ever, are the ultimate tool to help tame the virus and allow people to return to some semblance of pre-pandemic life. Despite the recent good news on their progress, though, it’s unclear whether they can truly deliver on the promise of a return to normal. Why? Because as much as some vaccines have proved effective in protecting against Covid-19 symptoms, they haven’t yet shown that they can stop the virus from spreading. In fact, some vaccine makers haven’t even tested for that. And that’s a problem.
Shots in development by Moderna Inc. and the partnership of Pfizer Inc. and BioNTech SE have shown stunning early success at reducing illness in infected patients. Just this week, Pfizer revealed that its vaccine was 94% effective in test subjects over 65 years old – the demographic group that needs the vaccine most. There’s still a lot left to learn, not least how protective these inoculations may be in the long run. But so far, there’s reason to believe that vaccines will induce the kind of immunity that Covid-19 survivors have developed. As for possible virus mutations, the latest vaccine technologies appear able to cope with them for now.