Some of the inserted people are still hiding. Here’s why you don’t have to worry.

When outbreaks occur, vaccines still provide good protection. A second CDC investigation examined an outbreak at a Kentucky nursing home; only half of the staff were fully vaccinated. The outbreak, which began with an uninserted worker, resulted in 46 cobid-19 infections. Of the 71 vaccinated residents, 18 (25%) were infected, two were hospitalized and one died. The staff walked better. Four (7%) of the 56 inserted workers were infected. Most of these infections were symptomatic. Only 6.3% of vaccinated residents and staff developed symptoms, compared with 32% of unvaccinated people.

When the nursing home explodes, “staff and residents are constantly exposed to the pathogen SARS-CoV-2 over and over again,” says Meagan Fitzpatrick, who models infectious diseases at the University of Maryland School of Medicine. So it’s gratifying to see such a small number of infections in this type of setting.

Variation tracking

New research suggests that variants may be to blame for some of these progressive infections. Viral variants are “one of the wildcards,” said Anthony Fauci, the U.S. president’s chief medical adviser. briefing on April 12, despite the paucity of real-world data, laboratory studies suggest that at least some of the variants are less susceptible to vaccine-induced antibodies than the original SARS-CoV-2.

In a Kentucky study, researchers found that the outbreak was driven by a variant known as R1, which had not been previously identified in the state. This virus had other important mutations, also identified in other variants. For example, the E484K mutation, also found in variant B.1.351, first identified in South Africa, appears to help the virus prevent antibody response. And the D614G mutation can increase transmissibility. The authors note that although the vaccine reduced the likelihood of infection and symptomatic disease, the virus managed to infect more than a quarter of the vaccinated residents and about 7% of the staff. This suggests that the vaccine may not work against this variant, but the authors warn that the research is small. (The authors of the Chicago study did not sequence the virus.)

Study of the New England Journal of Medicine He monitored infections at staff at Rockefeller University in New York. From January 21 to March 17, the researchers tested 417 employees who received the full course of the Pfizer or Moderna vaccine. Both women tested positive. When the researchers sequenced the viruses, they found that each was a different variant, and that they were not at all specific to those previously identified.

One woman, for example, had a variant with mutations found in B.1.1.7, which originated in the United Kingdom, along with the usual mutations in B.1.526 that occurred in New York. “There were variations somewhere between the two,” says Robert Darnell, a Rockefeller physician and biochemist and author of the study.

Darnell says that when an infection progresses, it is believed that the patient has not achieved a strong immune response to the vaccine. That doesn’t seem to be the case for women. Darnel was able to get a blood sample shortly after being positive. He and his colleagues found high levels of antibodies capable of neutralizing SARS-CoV-2. Since it was newly infected, the antibody response occurred as a result of the vaccine, not least due to a recent infection. Antibodies take some time to develop.

It is not entirely clear why his immune system did not protect him from infections, but one possibility is that the variant managed to prevent his response. “For this particular patient, that’s probably the best explanation of what we saw,” says Stephen Kissler, an epidemiologist at Harvard’s TH Chan School of Public Health. “It is not surprising to me that many of these progressive infections that we are seeing are of varying degrees,” he added. As more and more people are included, “there is pressure from evolutionary selection.”

On the other hand, as more people are vaccinated, we will see fewer infections and will be less likely to mutate the virus. And as Fitzpatrick points out, even if the immune leak explains the woman’s infection, it’s the only case. And there is no evidence that the infection was given to others who were vaccinated. The phenomenon is worthwhile for future studies, but “I still don’t see that as worrisome,” he says. “There is still no public health crisis.”

And even when advanced infections do occur, it doesn’t necessarily mean the vaccine has failed, says Monica Gandhi, an infectious disease doctor in San Francisco, California. Antibodies are only part of the immune response. T cells also play a huge role in raising other parts of the immune system and clearing the virus after it enters the body. They do not prevent infection, but they can prevent the spread of the virus. Some studies suggest that the body’s response to T cells will be much harder to prevent. “You can actually have a mild infection, but hopefully you will have protection against serious diseases,” says Gandhi.

However, it is important to monitor infections for progress to look for unexpected changes. An increasing number of infected people can lead to a decrease in immunity or the emergence of a new variant that can prevent an immune response. Vaccines should be adjusted, and booster shots could occur. But over time, “our body will develop a more complete immune response,” Kissler says. “And even if we pollute again, we will be protected from the worst results. In the long run, the outlook is good. ”