Scientists were alert after the increase in infections with the "ghost" strain of Omicron What did they know about it?

Scientists are now monitoring an increase in infections with a sub-strain of Omicron known as PA2 that is beginning to replace PA1 in parts of Europe and Asia.

The highly contagious mutated Omicron strain of the coronavirus, the most common form of which is known as PA1 (PA1), is behind nearly all cases of the virus today, although huge jumps in infections have already peaked in some countries.

Scientists are now monitoring an increase in infections with a sub-strain of Omicron known as PA2 that is beginning to replace PA1 in parts of Europe and Asia.

Subspecies "Ghost"

The PA1 strain represented 98.8% of infections referred to the GISAID Initiative, a database that monitors virus strains, as of January 25. But the World Health Organization said that several countries have recently recorded an increase in the infection of the sub-strain (PA2).

In addition to PA1 and PA2, WHO lists two other subspecies under the Omicron umbrella: PA1.1.529) and PA3. The breeds are genetically closely related, but each exhibits mutations that can change how it functions.

Trevor Bedford, a virologist at the Fred Hatt Shenson Cancer Center that monitors the development of Corona, said on Twitter on Friday that (PA.2) is responsible for 82% of infections in Denmark, 9% in Britain and 8% in the United States, and that On the basis of his analysis of sequence data from the GISAID database and injury statistics from the Our World in Data project at the University of Oxford.

The PA1 version of the Omicron strain is relatively easier to track than previous strains. This is because PA1 does not have one of the three genes targeted by the PCR test.

And PA2 (sometimes known as the "ghost") subspecies does not have the same missing target gene.

Instead, scientists monitor them in the same way as previous strains, including Delta, by tracing the genomes of viruses referred to public databases such as GISAID.

Is PA2 more contagious?

Early reports suggest that PA2 may be more contagious than the already highly contagious PA1, but there is no evidence yet that it is likely to resist vaccine protection.

Danish health officials estimate that the susceptibility of PA2 to spread may be one and a half times greater than that of PA1, based on preliminary data, although it is not likely to cause more serious symptoms.

In England, a preliminary analysis of contact tracing from December 27, 2021 until January 11, 2022, conducted by the Health Security Agency in the United Kingdom, indicates that the rate of transmission of infection at home is higher among contacts with those infected with the copy (PA.2), reaching 13.4% compared to 10.3% in other Omicron strains.

The British agency found no evidence of a difference in the effectiveness of vaccines against these strains, according to the report issued on January 28.

An important question, says Dr. Egon Ozer, an infectious disease expert at Northwestern University's Feinberg School of Medicine in Chicago, is do people infected with PA1 get protection from PA2?

He added that this question is of interest in Denmark, where some places have reported high PA1 cases and increased PA2 cases.

The good news, he said, is that vaccines and booster shots still "prevent people from hospitalization and death."