COVID-19 is still an enigma. The United States Centers for Disease Control and Prevention (CDC) again recommended two days ago to wear masks indoors to those vaccinated against COVID-19 more than two months after announcing otherwise. According to the latest guide from the health authority, Fully vaccinated persons are advised to wear face masks in “Closed public environments” in places with “substantial” or “high” transmission levels, as well as the use of these in schools for the next school year.
Last May, the CDC had withdrawn the chinstrap directive for vaccinated people in the United States, but cities like Los Angeles and Philadelphia reestablished the mandate. Community transmission and personal risk levels are two factors to consider, according to experts.
COVID vaccines have been shown to be effective against the harsher versions of the disease that lead to hospitalization and death. But experts say It is not the same for everyone and that people must consider factors such as community transmission, personal risk levels and their own risk tolerance to decide what is in their best interest.
The new council of “Masking” The CDC was based in part on data showing that the virus can thrive in the airways of vaccinated people. Now new findings are expected for tomorrow Friday.
The recommendation that vaccinated people in some parts of the country dust off their masks was largely based on a troubling finding, according to Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention. “New research showed that vaccinated people infected with the Delta variant carry huge amounts of the virus in their noses and throats, “he said. Walensky a The New York Times.
The find contradicts what scientists had observed in vaccinated people infected with earlier versions of the virus, most of whom appeared unable to infect others. That conclusion was a severe blow to Americans: People with so-called breakthrough infections (cases that occur despite full vaccination) of the Delta variant can be just as contagious as unvaccinated people, even if they have no symptoms.
That means Fully immunized people with young children, elderly parents, or friends and family with weak immune systems will need to renew vigilance, particularly in high-transmission communities. Vaccinated Americans may need to wear masks to protect not only themselves, but everyone in their orbit as well.
This new measure comes amid concern about the dangerousness of the Delta variant and at a time where in the United States there are 67,000 cases new per day on average. If vaccinated people transmit the Delta variant, they may be contributing to the increases, although probably to a much lesser degree than unvaccinated people.
The CDC has yet to release its data, frustrating experts who want to understand the basis for the change in opinion on the masks. Four scientists familiar with the research said it was compelling and justified the CDC’s advice that vaccinates wear masks again in indoor public spaces.
The investigation was conducted by people outside the CDC., the scientists said, and the agency is working quickly to analyze and publish the results. The agency expects to publish the investigation on Friday, an official said.
Some of the investigations may be related in part to an outbreak in Provincetown, Massachusetts, where the July 4 festivities have caused 882 cases as of Thursday. Almost three-quarters of those people were fully vaccinated. The agency has also tracked data from the Covid-19 Sports and Society Workgroup, a coalition of professional sports leagues that tests more than 10,000 people at least daily and sequence all infections.
“It is not yet clear how common progressive infections are and how long the virus persists in the body in those cases. Advances are rare and unvaccinated people account for most of the virus transmission “said Dr. Walensky. Reviews suggest that even fully immunized people can be reluctant vectors of the virus. “We think they could do it on an individual level, so we updated our recommendation,” added Walensky.
The new data does not mean that the vaccines are ineffective. Vaccines still powerfully prevent serious illness and death, as they were supposed to, and people with breakthrough infections rarely end up in a hospital.
About 97 percent of people hospitalized with Covid-19 are not vaccinatedaccording to CDC data But scientists warned even last year that vaccines might not completely prevent infection or transmission. Earlier versions of the virus rarely crossed the immunization barrier, prompting the CDC to warn in May that vaccinated people can go indoors without masks.
The usual rules do not seem to apply to the Delta variant
The variant Delta is twice as contagious as the original virus, and one study suggested that the amount of virus in unvaccinated people infected with Delta could be 1,000 times greater than that seen in people infected with the original version of the virus. Anecdotes of breakthrough infection clusters have become increasingly prevalent, with clusters of vaccinated people reporting colds, headache, sore throat, or loss of taste or smell, symptoms of an upper respiratory infection.
But the vast majority do not end up needing intensive medical care, because the immune defenses produced by the vaccine destroy the virus before it reaches the lungs. “We will continue to see a huge, huge, huge impact on the severity of illness and hospitalization,” said Michal Tal, an immunologist at Stanford University. “That’s really what the vaccine was made for.”
Coronavirus vaccines are injected into the muscle, and most of the antibodies produced in response remain in the blood. Some antibodies can reach the nose, the main port of entry for the virus, but not enough to block it. “Vaccines are beautiful, they work, they are incredible,” said Frances Lund, a viral immunologist at the University of Alabama at Birmingham. “But they are not going to give you that local immunity.”
When people are exposed to any respiratory pathogen, it can find a foothold in the mucous lining of the nose, causing no harm beyond that. “If you walk down the street and take samples from people, you will find people who have viruses in the mucosa that are asymptomatic “said Dr. Michael Marks, an epidemiologist at the London School of Hygiene and Tropical Medicine. “Our immune system is mainly fighting these things most of the time.”
But the Delta variant seems to bloom on the nose, and its abundance may explain why more people than scientists expected are experiencing infections and cold-like symptoms.
Still, when the virus tries to penetrate the lungs, the immune cells of vaccinated people swell and quickly clear the infection before it causes much havoc. That means vaccinated people must be infected and contagious for a much shorter period of time than unvaccinated people, Dr. Lund said.
“But that does not mean that in those first days, when they are infected, they cannot transmit it to another person”added.
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