Health

Omicron subvariant ba.2 more infectious than ‘original’, Danish study finds

The study,
which analysed coronavirus infections in more than 8,500 Danish households
between December and January, found that people infected with the ba.2
subvariant were roughly 33 percent more likely to infect others, compared to
those infected with ba.1.

Worldwide,
the “original” ba.1 subvariant accounts for more than 98 percent of omicron
cases, but its close cousin ba.2 has quickly become the dominant strain in
Denmark, dethroning ba.1 in the second week of January.

“We
conclude that omicron ba.2 is inherently substantially more transmissible than
ba.1, and that it also possesses immune-evasive properties that further reduce
the protective effect of vaccination against infection,” the study’s
researchers said.

The study,
which has not yet been peer-reviewed, was conducted by researchers at Statens
Serum Institut (SSI), Copenhagen University, Statistics Denmark and Technical
University of Denmark.

“If you
have been exposed to omicron ba.2 in your household, you have 39 percent
probability of being infected within seven days. If you instead had been
exposed to ba.1, the probability is 29 percent,” lead study author
Frederik Plesner told Reuters.

That
suggests ba.2 is around 33 percent more infectious than ba.1, he added.

BA.2 cases
have also been registered in the United States, Britain, Sweden and Norway, but
to a much lesser extent than in Denmark, where it accounts for roughly 82
percent of cases.

The study
also showed that ba.2 was relatively better than ba.1 at infecting vaccinated
and booster-vaccinated people, indicating greater “immune evasive
properties” of the subvariant.

But vaccines
still played an important role, the study underlined, since both
booster-vaccinated and fully vaccinated individuals were less like to get
infected and transmit either subvariants, compared to those not vaccinated.

See also  ‘Everyone’s looking for plastic.’ As waste rises, so does recycling

Preliminary
analysis by SSI has shown that there is no difference in the risk of hospitalisation
for ba.2 compared to ba.1.

The study
also confirms preliminary analysis from England, which showed ba.2 appears to
have a substantial growth advantage over the ba.1 type, according to Britain’s
UK Health Security Agency.

Related Articles

Back to top button