In retrospect, it was probably a mistake to remove the mask. But what are you going to do? David Flint and his wife had to check on their father in the Bronx. Flint’s wife is his father’s domestic health assistant, and the older man had just returned from foot surgery. For more than an hour, they all sat by the bed – Flint, his wife and his sister-in-law. It is a long time to wear a mask when not everyone does. “After a while, I took it off,” said Flint.
Flint was already vaccinated against COVID-19, so he assumed he would be immune. A social worker in New York who provides home hospice services for the dying, he was one of the first people in the country to get the vaccine. When he sat in his father-in-law’s room on January 19, he had been fully vaccinated for a week. The odds were in your favor.
But the odds are fickle. In a game of chance, not everyone wins, even if the chances of victory are high. Flint rolled over … and he lost, diagnosed with an asymptomatic case of COVID-19 on January 25. This, in itself, was not a shock. He knew that some people would still get the virus, despite being vaccinated. Even the famous “95 percent effectiveness” of mRNA vaccines was really a measure of how well the vaccines prevented symptomatic cases. But Flint did not expect to be one of the people who would escape through the cracks. Most importantly, though, he expected someone to care. “I thought there would be a mechanism,” he said. But no one asked him about his vaccine status when he was tested. There was nowhere to record this information with your doctor. And that was the part that confused Flint. “Shouldn’t anyone want to know?” he asked.
Yes, they should. And they do. Efforts are already underway to gather information that will 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 individuals who contract the disease?” are two different issues.
This 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 “effectiveness” and “effectiveness”. Effectiveness is the 95 percent figure obtained in a clinical trial. Effectiveness is the number when you are vaccinating millions more people, some of whom will be older, sicker or more likely to be exposed to a virus than trial participants. It’s a metric that covers all the real-life confusion, including that vaccines won’t always be administered optimally, said Dr. Kelly Moore, deputy director of the Immunization Action Coalition, an organization that works with the Centers for Disease Control. and Prevention to educate the public about vaccines. “You have people who forget to come back for a second dose or come back late. There may be a dosing error or storage problem, ”she said. And that even before you start to wonder if new variants like B.1.1.7 – originally found in the UK, but expected to become dominant in the U.S. in March – may be more resistant to vaccines than variants against which these vaccines were tested back in the fall.
The CDC will track the effectiveness of the real-world COVID-19 vaccine in several studies, using different methodologies in different locations at different times. Some studies – such as one that tracks groups of vaccinated and unvaccinated health professionals over time – are already underway.
Other studies are just beginning. An effort by the CDC will piggyback on an existing system designed to track the effectiveness of flu vaccines. At five medical research centers – in Michigan, Pennsylvania, Texas, Washington and Wisconsin – each person who arrives with a cough or other respiratory symptoms can become a study participant. All of them will be tested for COVID-19. Those with a positive test are the cases; those with a negative test become the controls. The researchers will then compare vaccination rates between the two groups. These studies are just beginning, because you cannot study the vaccine until people actually start taking it.
“It is only when the vaccine is distributed to larger segments of the population that it becomes viable. We are only reaching that point now in Wisconsin, ”said Dr. Ed Belongia, director of the Center for Clinical Epidemiology and Population Health at the Marshfield Clinic Research Institute – the Wisconsin flu vaccine research center – on February 11 “You can’t learn anything when only 1 percent of the population is vaccinated. “
The CDC is taking several approaches to this because the real world lacks something that is easier to control in a clinical trial: randomization. Unlike that laboratory environment, you cannot choose some people to receive the vaccine while denying others. What’s more, people don’t enroll in clinical trials at random, and that affects the results. People who wish to participate in a study may differ in some aspects from the population as a whole. Doing different types of studies that compare groups in various ways helps to reduce some of the uncertainties in overall results.
But none of these efforts will study the vaccine’s effectiveness by counting all individual cases like Flint’s. Over there It is The CDC’s research aimed to do this, but it is not about the vaccine’s effectiveness. Instead, this project, in partnership with state health departments, aims to identify trends in who the vaccine it is not working for.
These methods of tracking vaccine effectiveness are not new, even if the virus is. Scientists study the effectiveness of the post-introduction vaccine for each new vaccine launched, said Dr. Katherine Fleming-Dutra, a member of the Vaccine Evaluation and Efficacy Team in the CDC Response COVID-19. And this research has been shown to be crucial for disease prevention.
For example, as part of an effort to eradicate measles in the United States, scientists began tracking the measles vaccine that was in existence in the 1980s. Studies taught them that a dose of that vaccine was not cutting, according to with Dr. Walter Orenstein, professor and associate director of Emory Vaccine Center at Emory University. In 1989, the CDC and the American Academy of Pediatrics began to recommend that everyone receive two doses. If you weren’t looking closely, it would have been easy to forget that a second dose was needed. The first dose of the measles vaccine is 93% effective. But the disease spreads so easily and quickly that 93 percent was not good enough, said Orenstein. With the second dose, the vaccine becomes 97 percent effective in preventing measles.
The flu vaccine, in turn, goes through this process every year. That’s why there is that network of research centers for CDC to use to study COVID-19. This system produces results on the effectiveness of the flu vaccine twice a year, and preliminary results can be combined with data from one or two months. But that does not mean that we will get results so quickly with the COVID-19 vaccines. As the entire public health system went to great lengths to explain last year, flu and COVID-19 are not the same thing – and no one I spoke to was willing to estimate how long the results of COVID-19 will take.
That’s because a series of complications will make it more difficult (and possibly take longer) to do the same types of studies for COVID-19. For example, seasonal flu has predictable annual control points at this point. Vaccines start to be launched in the fall. In December or January, when flu cases really start to increase, all those who will be vaccinated have already been vaccinated, and the proportion of Americans who are vaccinated is approximately the same from year to year. With COVID-19, scientists are examining a disease that has high prevalence in some places and not in others, in addition to launching new vaccines.
There are other challenges to monitoring the effectiveness of COVID-19 vaccines, said Emily Martin, professor of epidemiology at the University of Michigan and co-director of the Michigan Influenza Center. Influenza networks have long depended on people who see a doctor to treat their respiratory symptoms. That’s where they apply for studies. But the expansion of the COVID-19 test has largely occurred outside of doctors’ offices, and these test centers may or may not leave a record of negative (or positive) diagnoses.
When the data finally arrives, it is likely to show us that David Flint is not alone in 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, “Do they work well?” it is not just about individuals. For example, when researchers studied the effectiveness of pneumococcal vaccines in the real world, they found that rates of the disease fell among older people, even though only children were being vaccinated. This is because children were the main carriers of the disease. As soon as they stopped contracting, so did their grandparents.
And the vaccine’s effectiveness is not just about how many people test positive. One thing we learned from the flu vaccine studies is that the vaccine can reduce the severity of the disease, even if you still get it after vaccination. These studies will help us to find out what is happening with COVID-19 as well. Things like that are important. After all, when Flint received COVID-19, he just had a sore throat. Their unvaccinated relatives, however, were worse off.