A study reveals the percentage of immunity formed after infection with Corona .. What is it?

A Danish study found the percentage of immunity developed after infection with the emerging corona virus (Covid-19), so what is it?

What data do we have about the Breton variant of the Corona virus that was discovered in France?

And is it really not detectable by examining the "polymerase chain reaction", and is it spreadable?

How dangerous is it compared to the rest of the mutated strains?

The answers are in this report, which summarizes the latest scientific data and studies about Corona.

We start from Denmark, where a large study published its results Thursday found that a recurrence of corona is rare, but it is more common among those over the age of 65, and the study - which was reported by the French Press Agency - found no evidence of a decline in immunity within a period ranging between 6 and 7 months. .

Sten Ethelberg, professor at the Statens Serum Institute (Copenhagen), and his colleagues used in their study data derived from the free "polymerase chain reaction" testing strategy adopted by Denmark in 2020, which authorized the examination of about 4 million people (69% of the country's total population).

The study found that the immunity formed as a result of infection with the virus is 80% among the youngest, compared to only 47% among those aged 65 and over, according to the study published in the journal "The Lancet", and includes a comparison of test results. BCR during the first epidemic wave (between March and May 2020) and the second epidemic wave (between September and November 2020) in Denmark.

The researchers also touched on the immunity of the medical staff, due to the high risk of exposure to the virus, and they estimated it to be 81.1%, a level close to the results of previous studies.

The Danish researchers pointed out that they "did not find any difference" in the level of immunity from recurrent infection in both sexes, nor did they find any evidence of a decline in immunity over a period of 6 to 7 months.

The study was interested in the original Covid-19 version, and did not address the modified version.

The following graphic shows the "calendar" of the Corona patient, that is, what happens to him from the first day of infection until recovery, and when it becomes non-contagious.

To know more details about the course of the disease, click on this link.

The Protanic mutated strain ... where did it appear?

And when?

In the report published by the French newspaper "lefigaro", the writer Jean Senchal says that on Monday, March 15th, the General Directorate of Health in France announced - in a press release - that "a new strain of Corona virus has been discovered in the Brutani region." Northwest France), '' PCR tests were unable to detect it.

At first glance, this information may seem alarming, but the General Directorate of Health confirmed that "the first analyzes of this new mutated strain are not as dangerous as other strains, and that their ability to spread is limited."

The author pointed out that a "mutated strain in the Brutani region" was discovered for the first time at the Lanyon Hospital Center, after a number of cases were detected on February 22nd, then after 3 weeks, and according to the General Directorate of Health, 79 cases were identified, including This includes 8 cases carrying the new mutated strain. "

Why could the protanic mutated strain not be detected by PCR assay?

The author explained that despite the emergence of clear typical symptoms indicating that some people were infected with the Coronavirus, the results of the tests conducted on the nasopharyngeal samples were negative.

"Two scenarios ensue: one reassuring and the other worrying," explained epidemiologist Pascal Cribi, a teacher and researcher in epidemiology and biostatistics at the Graduate School of Public Health.

Regarding the "reassuring" scenario, the fact that the virus was not detected in the upper airways means that it is not present and that it quickly migrated to the lungs.

But this also means that it will be less contagious, because the main pathway of infection - the aerosol - will be less.

In the context of the worrying scenario, the negative results of the "polymerase chain reaction" examination are confirmed, or also that the virus has mutated enough to be undetectable, which would represent a real problem in diagnosing the infection, because cases of infection cannot be easily tracked or detected. .

And if Pascal Cribi preferred the first scenario, because the virus "was discovered in the lungs as soon as deep tests were performed," the question that arises is: "How did it transmit between these people if it was less contagious?"

A table comparing the currently existing Corona vaccines in terms of price, effectiveness, doses and storage temperature (Al-Jazeera)

Could the Protanid mutant strain spread to other areas?

"If we are unable to detect one of the mutated strains, then this may mean that it has already spread to other areas without us realizing it," Pascal Crepe explains.

The investigation into this viral mass is underway for several weeks, and local authorities, governorates and the Regional Health Agency have taken measures to limit the spread of the virus, especially by "speeding up vaccination, and reminding you of the importance of maintaining physical distancing and limiting gatherings, and epidemiological monitoring of the population has also been conducted."

The French authorities warned of the emergence of possible symptoms in the surrounding population, but these cases were not suspected of carrying the new mutated strain. ”According to him, the situation appears under control.

Seasonal infection

On Thursday, the United Nations did not rule out that the spread of Covid-19 would become seasonal, but made clear that the data is still insufficient to suggest relying on weather and air quality to adapt measures to combat the pandemic.

The World Meteorological Organization of the United Nations formed a working group of 16 experts to study the impact of meteorological factors and air quality on the spread of the virus.

In their first report, experts estimated that the seasonality of respiratory viral diseases that worsen at the height of the cold season suggests that Covid-19 "will likely be a seasonal disease if it lasts for several years."

The study also showed that its spread "may become seasonal over time, which indicates that it may be possible to rely on meteorological factors and air quality to monitor and predict disease" in the future.

But they considered that it is too early to rely on weather factors and air quality, and they indicated that the mechanisms to control the spread of the Covid-19 virus last year "were mainly based on government interventions and not on meteorological factors."

"At this stage, the available data do not support the governments' use of weather and air quality factors to reduce infection control measures," said Ben Zicek, co-director of the expert group and professor at Johns Hopkins University.

"In the first year of the epidemic, we noticed waves of infections in warm seasons and in warm regions, and there is no evidence that this will not recur in the next year," he added in a statement.

The World Meteorological Organization stated that while laboratory studies have found some evidence that the virus lives longer in cold and dry conditions, it has not yet been determined if weather factors have a significant impact on infection rates in real conditions.

The team concluded that there is still no conclusive evidence about the influence of factors related to air quality.

Despite the presence of preliminary data that poor air quality raises death rates, experts indicated that it has not been proven that pollution has a direct effect on the spread through the air of the Corona virus.