Confirmed consecutively in Hong Kong and Singapore
Europe recently classified it as a 'Variant of Concern'
Immune evasion increases possibility of reinfection
[Asia Economy Reporter Kim Young-won] The Omicron subvariants BA.4 and BA.5, which have driven the resurgence of COVID-19 in South Africa, have also been detected in Europe and Asia.
On the 15th, the Singapore Ministry of Health announced that two cases of BA.4 and one case of BA.5 had been confirmed. According to the Ministry, this is the first time these two variants have been found in Singapore, and all three cases were individuals who had completed their third vaccine dose.
Earlier, among Asian countries, one case of BA.5 was confirmed in a South African entrant in Hong Kong on the 14th of last month. The Hong Kong Department of Health also announced that three cases of BA.4 were detected?two on the 12th and one on the 14th of this month. In Oceania, New Zealand confirmed BA.4 and BA.5 for the first time on the 1st and 8th, respectively.
The European Centre for Disease Prevention and Control (ECDC) recently reclassified BA.4 and BA.5 from variants of interest to variants of concern. In Portugal, the proportion of BA.5 has recently increased, leading to a rise in new confirmed cases. According to the ECDC, as of the 8th, BA.5 accounted for 37% of cases in Portugal and is expected to become the dominant strain around the 22nd.
The BA.4 and BA.5 variants are sublineages of Omicron (BA.1) and have been reported to possess immune evasion capabilities. South African researchers collected blood samples from individuals who had recovered from the general Omicron variant and tested their defense against BA.4 and BA.5. The results showed that in unvaccinated groups, neutralizing antibody levels were reduced to one-eighth compared to BA.1, and in fully vaccinated individuals, neutralizing antibodies decreased to about one-third.
However, changes in severity compared to BA.1 have not yet been determined. The ECDC explained that while BA.4 and BA.5 are not expected to cause significantly increased severity compared to BA.1 and BA.2, a rapid surge in confirmed cases could proportionally increase the number of hospitalizations.
Professor Baek Soon-young, Emeritus Professor at the Catholic University School of Medicine, stated, "The immune evasion property is due to amino acid mutations that prevent antibodies developed so far from binding well," adding, "Because of this, even those previously infected with Omicron can be reinfected, but the symptoms are expected to be mild."
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