By Julie Steenhuysen

CHICAGO, (Reuters) – Nearly all global coronavirus cases are now caused by the transmissible Omicron strain of SARS.

Scientists have noticed a spike in the number of cases related to BA.2, a distant cousin that has begun outperforming BA.1 across parts Europe, Asia. Below is what we have so far learned about the subvariant.

“STEALTH” SUPBVARIANT

Globally, BA.1 represented 98.8% in sequenced cases sent to GISAID public virus tracking database GISAID on Jan. 25, The World Health Organization reports that there has been an increase in BA.2 subvariant numbers.

The WHO also lists BA.1 as well as BA.2 under Omicron. Although they are all genetically related, each one has mutations that can alter their behavior.

Trevor Bedford, who is a computational virusologist at Fred Hutchinson Cancer Center, has written on Twitter (NYSE.) that BA.2 makes up roughly 82% of SARS-CoV-2 cases in Denmark. It also represents 9% in Britain and 8% in America. His analysis of sequencing data and counts from The Our World in Data Project at the University of Oxford reveals that BA.2 constitutes approximately 8% of SARS.

It has been easier to trace the BA.1 Omicron version than previous variants. This is due to BA.1 missing one of the three target genes in a common PCR testing. This pattern was assumed to have been caused by BA.1.

BA.2, also known as “stealth”, does not contain the missing target gene. Scientists are instead monitoring the virus genomes that have been submitted to databases like GISAID, in the same manner as they did with Delta.

Experts said that coronavirus home testing kits can detect infection with BA.2 just like other variants. However, they are not able to identify which variant.

MORE TRANSMISSIBLE

Early reports suggest that BA.2 might be more contagious than BA.1, although there has been no proof that this virus is more susceptible to vaccine protection.

Based on preliminary data, Danish health officials believe that BA.2 is 1.5 times more likely to be transmissible than BA.1. However it does not seem to cause any more serious disease.

An analysis of contacts from December 27, 2021 through January 11, 2022 by the UK Health Security Agency has shown that there is a higher rate of household transmission among people who have been infected (13.4% vs 10.3% for Omicron cases).

According to the Jan. 28, report, HSA did not find any evidence that vaccines were more effective.

Critical question: Will people infected with the BA.1 strain of bacteria be protected by BA.2? Dr. Egon Ozer, an infectious disease specialist at Northwestern University’s University Feinberg School Of Medicine in Chicago, said that it is crucial to know.

This has caused concern in Denmark where there were high cases of BA.1 infection and some areas that reported rising BA.2 infections, Ozer stated.

Ozer stated that if a prior BA.1 infection doesn’t protect against BA.2, then “this could kind of be sort of a one-humped camel type of wave.” It’s still too soon to predict if this will occur.

He said that the good news is that boosters and vaccines “keep people out hospital beds and prevent people from getting sick.”