With the rapid rise of COVID-19 cases in most parts of the United States again, the U.S. Centers for Disease Control and Prevention is now comparing the infectivity of the Delta variant with the infectivity of chickenpox, one of the most infectious viruses in the world.

One Internal documents According to reports, the slide presentation from the CDC provides an overview of unpublished data on the Delta variant, indicating that it may spread at the same rate when unvaccinated people and fully vaccinated people contract breakthrough infections, regardless of Whether they have symptoms. It also seems to cause more serious diseases.

The file was first created by Washington postIt still says that vaccinated people are three times less likely to be infected with COVID-19 than unvaccinated people, and 10 times less likely to die from the virus.

“I think people need to understand that we are not crying wolves here. This is serious,” Dr. Rochelle Varensky, director of the CDC, told CNN, To confirm the authenticity of internal documents. “This is one of the most contagious viruses we know. Measles, chickenpox, this – they are all there.”

In view of the latest findings, the CDC again recommends that fully vaccinated people wear masks indoors where COVID-19 continues to spread or where the spread of COVID-19 is high.

Pennsylvania and much of the Northeast are not one of the states with the largest surge of COVID-19 in recent weeks, but despite the relatively high level of vaccination in these states, the transmission rate is clearly on the rise.

In Pennsylvania, the state health department 1,110 new COVID-19 infections were reported on FridayAs of Wednesday, the 7-day average was 815, a five-fold increase since July 4. The number of people hospitalized with COVID-19 in the state is also increasing.

Philadelphia officials Highly recommended last week The vaccinated people resume wearing masks in indoor public places on the grounds that the number of infected children who need to be hospitalized is small but increasing. Children under the age of 12 are still not eligible for the COVID-19 vaccine, and they are also worried about becoming a vector of the virus, especially when they are preparing to return to school in the fall.

According to reports, CDC documents indicate that breakthrough cases among vaccinated people may begin to account for a larger proportion of overall COVID-19 cases in the United States. One estimate suggests that among the 162 million Americans currently vaccinated, there are approximately 35,000 symptomatic infections every week. This makes the number of asymptomatic cases and their spread in this group an increasingly urgent issue, as about half of Americans are still unvaccinated.

Dr. Walter Orenstein of Emory University said: “The most important thing is that compared with other variants, even if vaccinated people are not sick, they still have similar levels of infection and transmission of the virus as unvaccinated people.” The Vaccine Center told CNN after reviewing the CDC file.

An even more disturbing finding in the new study is that elderly people over 60 years of age vaccinated with Delta variants seem to be less protected than previous variants—about 97% of people are protected from early Alpha variants, while Delta The protection rate of the variant is only 85%, According to an Israeli study.

Other data currently collected by Pfizer Point out that the vaccine’s effectiveness decreases after six monthsThe chief executive of the pharmaceutical giant, Albert Bourla, said this week that the percentage had fallen from about 96% to 84% in the first two months.

The emerging situation is beginning to point more clearly COVID-19 booster injections may be needed Provide strong protection for people who have been vaccinated.

CDC officials stated that new communication challenges regarding the COVID-19 vaccine need to be addressed. They worry that many unvaccinated people will continue to avoid vaccinations because of misunderstandings about their effectiveness in preventing serious diseases.

“If we get 70% of the population vaccinated, we won’t get into trouble,” Dr. Eric Topol, director of the Scripps Research and Translation Institute in California, said in an interview. USA Today“When more than half of your population is not (fully) vaccinated, you are vulnerable.”

Dr. Robert Wachter, head of the Department of Medicine at the University of California, San Francisco, told USA Today that the increasing understanding of the virus’s direction suggests that more stringent public health measures may need to be restored for an uncertain period in the future.

“None of this is good news,” Wachter said. “Obviously (we) need more vaccinations and resume non-pharmacological interventions as soon as possible. Even for people who have been vaccinated, there may be boosters.”