Yes, We Have COVID-19 Vaccines That Are 95% Effective. But That Doesn’t Mean the End of the Pandemic is Near

It’s a rare glimmer of hope in a brutal and battering pandemic year: in November, both Moderna and Pfizer reported that their much-anticipated COVID-19 vaccines are 95% effective in protecting people against getting sick with the disease.

Scientists were encouraged (and even surprised by the magnitude of the protection), public health officials finally saw what could be the beginning of the end of the pandemic, and families everywhere began fantasizing about a return to normalcy where gathering around the table to celebrate the holidays are a given and not a matter of public health concern.

But the same public health experts who are encouraged by the positive vaccine results are also warning that vaccines aren’t the panacea that many are desperately hoping they will be. And that, even after more people get the shots, we’ll still have to wear masks and stay a respectful six feet apart from each other.

First, there’s the question of efficacy. Yes, Moderna and Pfizer reported that their shots are 94.5% and 95% effective, respectively. But that efficacy refers to the vaccines’ ability to protect against COVID-19 disease—and not necessarily against infection with the virus. Both of the rigorous trials to test the vaccines were designed to measure COVID-19 illness—trial volunteers were randomly given either the vaccine or a placebo, and then asked to report any symptoms of COVID-19 they experienced, such as fever, cough, shortness of breath or muscle aches. The study researchers then determined whether or not to test them. If people tested positive, they were logged as a confirmed COVID-19 case, and the researchers then looked at the group of COVID-19 cases and compared how many people had been vaccinated versus how many had gotten placebo. The effectiveness measured whether these people went on to develop more symptoms of COVID-19.

That means that people who are vaccinated are not necessarily immune to getting infected; but they are more likely to experience fewer symptoms and not get as sick as those who aren’t vaccinated.

That’s still a huge advantage over the virus, since severe COVID-19 sends people to the hospital where they may need intensive care and ventilators to breathe. The more people who can experience milder symptoms and recover at home, the less burden on the health care system and the less exposure that health care workers will have to the virus, which all contributes to better control of the pandemic.

However, because the vaccines do not necessarily protect against infection, that means that public health measures such as wearing masks, social distancing and avoiding indoor gatherings are still critical to containing the virus. More data will provide clues about whether people who are vaccinated and never experience symptoms can still spread the disease to others. But that’s not known yet, so experts say it’s better to keep up the behaviors that have proven to stymie spread of COVID-19.

In addition, while both Moderna and Pfizer plan to file shortly for authorization to start distributing their vaccines, even after they receive the green light, it will take a while for the shots to be shipped and actually arrive at hospitals, doctors’ offices and pharmacies. Both companies have already begun producing doses, banking on the fact that their vaccines would be effective, but that manufacturing still won’t churn out enough doses to meet demand this year.

Because doses will be limited, the government has asked state health departments to submit proposals for how they will distribute vaccines in phases, starting with highest-risk groups like health care workers and other frontline workers with essential jobs such as first responders and law enforcement personnel. As more doses become available, the elderly and people with chronic health conditions would be vaccinated, and eventually, the rest of the population. It’s likely that the majority of the American public won’t be vaccinated until next spring at the earliest.

That means that the ultimate goal in controlling the pandemic, herd immunity, likely won’t happen until well into next year, when enough people are vaccinated and can ward off serious illness. “Not until a substantial proportion of the population is vaccinated, and the caseload has dropped to very low levels, will we be able to breathe (without a mask) a sigh of relief,” says Emanuel Goldman, professor of microbiology at Rutgers University. And even then, he points out, researchers will have to remain vigilant about tracking any changes in the virus as it finds fewer and fewer welcoming hosts. “The virus might have other ideas and try to change in a way that makes the vaccine less effective.”

Only by vaccinating millions of people, and monitoring how their immune systems react, will experts get a better handle on what it takes to extinguish COVID-19 or at least make it much more difficult for it to spread. “The big message is that we have an additional tool [in the form of vaccines] for fighting COVID-19, but we don’t have a tool to replace everything we do just yet,” says Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “Hopefully as the country and world gets massively vaccinated, this virus will be essentially backed in, with no place to go because everybody is protected.”

With reporting by Amy Gunia/Hong Kong