So you got vaccinated … and then you got COVID. Now what?

In hindsight, it was probably a mistake to remove the mask. But what are you going to do? David Flint and his wife had to see their father in the Bronx. Flint’s wife is his father’s home health aide, and the older man had just come home from foot surgery. For more than an hour, they all sat by the bed: Flint, his wife, and his sister-in-law. It’s time consuming to wear a mask when not everyone else does. “After a while, I took it off,” Flint said.

Flint was already vaccinated against COVID-19, so he assumed he would be immune. A social worker in New York who provides palliative care services at home to the dying, he was one of the first people in the country to receive the vaccine. By the time he sat in his father-in-law’s bedroom on January 19, he had been fully vaccinated for a week. The odds were in his favor.

But the odds are fickle. In a game of chance, not everyone can win, even if the odds of winning are high. Flint rolled … and lost, diagnosed with a mostly asymptomatic case of COVID-19 on January 25. That alone was not a surprise. I knew that some people would still get the virus despite being vaccinated. Even the famous “95 percent efficacy” of mRNA vaccines was actually a measure of how well the vaccines prevented symptomatic cases. But Flint didn’t expect to be one of the people who slipped away. More importantly, though, I hoped someone would care. “I thought there would be some mechanism,” he said. But no one asked him about his vaccination status when he was tested. There was nowhere to present that information to your doctor. And that was the part that confused Flint. “Shouldn’t someone want to know?” I ask.

Yes, they should. And they do. Efforts are already underway to gather information to help scientists understand how effective COVID-19 vaccines are in the real world. But “How well do vaccines work?” and “Should we count all vaccinated people who get the disease?” they are two different questions.

That complication begins with some basic facts about the effectiveness of the Pfizer and Moderna vaccines currently available in the United States. Scientists say there is a difference between “efficacy” and “effectiveness.” Efficacy is the 95 percent number you get from a clinical trial. Efficacy is the number once millions more people are vaccinated, some of whom will be older or sicker or more likely to be exposed to a virus than trial participants. It’s a metric that encompasses all of the real-life disorder, including that vaccines won’t always be delivered in the ideal way, said Dr. Kelly Moore, deputy director of the Immunization Action Coalition, an organization that works with the Centers for Disease Control. Disease and Prevention to educate the public about vaccines. “There are people who forget to take a second dose again or come back late. Maybe there is a dose administration error or a storage problem, ”he said. And that’s even before you start looking into whether newer variants like B.1.1.7, originally found in the UK but expected to be dominant in the US in March, might be more resistant to the vaccines than the variants that those vaccines were tested against. back in the fall.

CDC will track the effectiveness of the COVID-19 vaccine in the real world in multiple studies, using different methodologies in different locations and at different times. Some studies, such as one that tracks groups of vaccinated and unvaccinated health workers over time, are already underway.

Other studies are starting to take off. A CDC effort will build on an existing system created to track the effectiveness of flu vaccines. At five medical research centers, in Michigan, Pennsylvania, Texas, Washington state and Wisconsin, everyone who comes in with a cough or other respiratory symptoms can participate in the study. All of them will be tested for COVID-19. Those that test positive are the cases; those that test negative become the controls. The researchers will then compare the vaccination rates between the two groups. However, those studies are just beginning because the vaccine cannot be studied until people actually start receiving it.

“It is only when the vaccine is spread to larger sectors of the population that it becomes feasible. Were only get to that point now in Wisconsin, ”said Dr. Ed Belongia, director of the Center for Clinical Epidemiology and Population Health at the Marshfield Clinical Research Institute, the research center for flu vaccine effectiveness in Wisconsin, February 11. learn something when only 1 percent of the population is vaccinated. “

The CDC is taking multiple approaches to this because the real world lacks something that is easier to control in a clinical trial: randomization. Unlike in that lab setting, you can’t choose some people to get vaccinated while denying others. Also, people don’t just enroll in randomized clinical trials, and that affects the results. People who want to participate in a study may differ in some respects from the general population. Conducting different types of studies that compare groups in various ways helps reduce some of the uncertainty in the overall results.

But none of these efforts will study the effectiveness of the vaccine by counting all individual cases like Flint’s. There is The CDC research aimed to do that, but it is not about the effectiveness of the vaccine. Instead, that project, a partnership with state health departments, is aimed at spotting trends in who vaccines are. It is not working for.

Those methods of tracking the effectiveness of the vaccine are not new, even if the virus is. Scientists study vaccine effectiveness after introduction for each new vaccine that comes out, said Dr. Katherine Fleming-Dutra, a member of the CDC’s Vaccine Evaluation and Effectiveness in the COVID-19 Response Team. And that research has proven crucial to disease prevention.

For example, as part of an effort to eradicate measles in the United States, scientists began tracking the measles vaccine from decades ago in the 1980s. Studies taught them that one dose of this vaccine was not enough. according to Dr. Walter Orenstein, professor and associate director of the Emory Vaccine Center at Emory University. In 1989, the CDC and the American Academy of Pediatrics began recommending that everyone receive two doses. If you weren’t looking closely, it would have been easy to miss that a second dose was necessary. The first dose of the measles vaccine is 93 percent effective. But the disease spreads so easily and quickly that 93 percent were not good enough, Orenstein said. With the second dose, the vaccine becomes 97 percent effective in preventing measles.

The flu vaccine, meanwhile, goes through this process every year. That’s why there is such a network of research centers that the CDC can use to study COVID-19. That system produces results on flu vaccine effectiveness twice a year, and preliminary results can be gathered from as little as a month or two of data. But that does not mean that we will have results just as quickly with COVID-19 vaccines. As the entire public health system has gone to great lengths to explain in the past year, flu and COVID-19 are not the same beast, and no one I spoke to was willing to estimate how long it would take for COVID-19 results.

This is because a number of complications will make it difficult (and possibly take longer) to conduct the same types of studies for COVID-19. For example, seasonal flu has, at this point, predictable annual checkpoints. Vaccines begin to be distributed in the fall. By December or January, when flu cases really start to rise, everyone to be vaccinated has already done so, and the proportion of Americans who are vaccinated is roughly the same from year to year. With COVID-19, scientists are looking at a disease that is highly prevalent in some places and not others, in addition to launching new vaccines.

There are other challenges in tracking the effectiveness of COVID-19 vaccines, said Emily Martin, a professor of epidemiology at the University of Michigan and co-director of the Michigan Influenza Center. Flu networks have long depended on people coming to see a doctor for their respiratory symptoms. That’s where they sign up for studies. But the expansion of COVID-19 testing has largely taken place outside of doctor’s offices, and those testing centers may or may not leave a negative (or positive) diagnostic record.

When the data finally comes in, it will likely show us that David Flint is not the only one contracting COVID-19 after receiving two doses of the vaccine. But these studies can also bring good news. That’s because the fun thing about vaccines is, “How well do they work?” it’s not just about individuals. For example, when researchers studied the real-world effectiveness of pneumococcal vaccines, they found that rates of the disease decreased among older people even though only children were vaccinated. That is because children were the main carriers of the disease. Once they stopped getting it, so did their grandparents.

And the effectiveness of the vaccine isn’t just about how many people test positive. One thing we have learned from influenza vaccine studies is that the vaccine can reduce the severity of the illness, even if you still get it after vaccination. These studies will also help us find out what is happening with COVID-19. Things like that matter. After all, when Flint contracted COVID-19, he only had a sore throat. However, their unvaccinated relatives were worse off.

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