Breakthrough infection: the new crown delta strain is 3 times that of other strains

The latest research shows that the delta mutant strain of the new coronavirus is three times more likely to have a breakthrough infection than other mutant strains
.
Breakthrough infection refers to the situation in which the vaccinated person is still infected more than 14 days after the vaccine is fully vaccinated

A recent study published on the medical preprint website medRxiv showed that between March 15 and July 24, 2021, in the Houston Methodist Hospital system, there were 194 (17.
4%) of the 1118 infected with the new crown delta strain.
) Are breakthrough infections; 220 (5.
8%) of the 3802 patients infected by other mutant strains are breakthrough infections
.
In other words, the breakthrough infection rate of the new coronavirus delta mutant strain is three times that of other strains

Studies from various countries have shown that although vaccination can reduce the incidence of critical illness and death, delta variants are more likely to spread among people who have been vaccinated against new crowns than other new crown variants
.
However, the researchers believe that vaccination is a necessary protective measure that can effectively reduce the severity of the disease after infection

How much is the Delta Virus infectious ability of a breakthrough infected person? A number of studies have confirmed the high virality of delta strain breakthrough infections and unvaccinated people
.

Another study published in the medRxiv preprint by researchers at the University of Wisconsin-Madison recently proved that the high viral load of the Delta strain is associated with high infectivity
.
The researchers compared the Ct values ​​of 719 people from June 29 to July 31 (a low Ct value means a high viral load)

The researchers cultivated infectious viruses from a subset of 55 samples with Ct values ​​<25
.
The test results showed that 14 (88%) infectious viruses were isolated from 16 samples from unvaccinated people, and 37 (95%) infectious viruses were isolated from 39 samples from vaccinated people

"It is basically certain that people who have
been vaccinated may actually spread the virus .
But we don't know what the relative role of vaccinated people in the spread of the virus in the entire community is

A report from the Centers for Disease Control and Prevention (CDC) in August showed that of the 469 new crown cases in Massachusetts, nearly three-quarters were vaccinated
.
Both vaccinated and unvaccinated people have very low Ct values, which means their high viral load

However, after being vaccinated, even if they are infected, their viral load will drop faster than those who have not been vaccinated
.
By tracking the viral load of vaccinated and unvaccinated people on a daily basis, researchers in Singapore found that although the viral load of vaccinated and unvaccinated people was similar at the initial stage of infection, the viral load of vaccinated people was 7 days after infection.

The study also found that people infected with the new crown vaccine are more likely to have asymptomatic infections, even if they have symptoms, the number of symptoms is relatively small
.
At the same time, compared with unvaccinated people, the proportion of vaccinated infected people who need to be supplied with oxygen and admitted to the ICU is relatively smaller
.

This result is consistent with the findings of the China Centers for Disease Control and Prevention weekly report previously reported by The Paper
.
The study is based on the case observations of three people infected with the new crown delta strain in Chengdu, Sichuan, and found that the vaccinated patients had shorter hospital stays, higher Ct values, and shorter time from positive nucleic acid test to positive antibody test
.

A large-scale analysis of Delta Communication comes from the UK’s REACT-1 (Community Communication Real-Time Evaluation Project), which is led by a team from Imperial College London and tests more than 100,000 British volunteers every few weeks.

.
The team analyzed the Ct values ​​of samples received in May, June and July
.
During this period of time, Delta is rapidly becoming the main mutant strain of the country's new crown transmission
.

The results released in the 13th round of REACT-1 report showed that among individuals who tested positive, the average viral load of those who had been vaccinated was lower than that of those who had not been vaccinated
.
According to one of the authors of the study and an epidemiologist at Imperial College Paul Elliott, these results are different from other Ct studies.
This may be due to the random sampling of the population, including those who tested positive but did not show symptoms.
People
.

"These findings, and the increase in young cases who have not yet received two doses of the vaccine, emphasize the effectiveness of two doses of vaccination to suppress delta variants
.
" Elliot said, "We believe that as many people as possible get two doses.
Vaccines, especially those young people, are really important
.
"