Thailand has 181 recorded cases of Covid-19's latest worrisome subvariants, BA.4 and BA.5, which are similar to the Delta variant and therefore potentially harmful to a patient's lungs, according to the Department of Medical Sciences.
Director-general Supakit Sirilak said on Friday that there had been 181 cases of BA.4 and BA.5 subvariants of the Omicron variant and they posed risks of infection clusters.
The 181 cases were confirmed among 400 samples and consisted of 48 infected arrivals and 133 local cases. Most of them were confirmed in Bangkok, where the most samples were collected for examination, Dr Supakit said.
On Tuesday Ramathibodi Hospital reported that since April the country had registered 49 cases of the two subvariants.
Dr Supakit said the mutation of BA.4 and BA.5 was similar to the Delta variant and posed lung inflammation risks.
He said BA.4 and BA.5 accounted for 45.8% of new Covid-19 cases, BA.2 53.8% and BA.1 the rest.
A person's antibodies were less effective against BA.4 and BA.5 than they were against other subvariants and some patients with low immunity responded less to medication, the director-general said.
BA.5 should be monitored closely because it was spreading and infections already confirmed in 62 countries, while BA.4 and BA.2 infections were falling. BA.5 was likely to become a dominant strain globally and locally, Dr Supakit said.
The people who had previously contracted other subvariants of Omicron could be infected with BA.4 and BA.5 strains. Those with enough antibodies and booster vaccine shots could better fight off a repeat infection, he said.
Omicron was the world's only variant of concern as it was the dominant variant, he said.
Dr Supakit acknowledged the government's decision to further relax Covid-19 controls and said the number of BA.4 and BA.5 cases had not risen significantly. Therefore, it was still unnecessary to intensify control measures, he said.