Barely a month after the Beta variant emerged in the deep South, it has managed to travel more than 1,000 kilometres north to Bangkok where COVID-19 cases were already surging by thousands each day.
On June 28, the Medical Sciences Department confirmed that a single Beta case had been found in the capital, triggering medical experts to sound the alarm.
What threat does Beta carry?
First detected in South Africa late last year, the Beta variant – also known as B1.351 – blunts the efficacy of most COVID-19 vaccines. In clinical trials, two doses of AstraZeneca vaccine proved to be only 10.4 per cent effective in preventing mild to moderate B1.351 infections.
Research at Boston Children’s Hospital in the US shows changes to spikes on the Beta variant mean antibodies generated by vaccines are less able to bind to the virus, which allows it to evade the immune system of even fully inoculated people.
As of Monday, more than 6.5 million people in Thailand had received at least one shot of a COVID-19 vaccine. The government aims to achieve herd immunity by delivering at least 100 million doses before year-end.
There is some good news, though. Researchers have learned that mutations in the Beta variant also make it less transmissible than other variants of concern, namely Alpha and Delta.
How did it enter Thailand?
Reports indicate that this variant first arrived in late May, when the Malaysian wife of a Thai man living in the border province of Narathiwat sneaked into the country and skipped the mandatory 14-day quarantine.
By the first week of June, 26 cases of Beta had been found in Narathiwat’s Tak Bai district. From June 21 to 27, Thailand recorded 90 Beta cases – 87 in Narathiwat and one apiece in Yala, Surat Thani and now Bangkok.
How did it arrive in Bangkok?
Dr Supakit Sirilak, director-general of the Medical Sciences Department, said the Beta case in Bangkok was confirmed on June 25. Track-and-trace efforts indicate the patient picked up the virus from his son, who recently travelled from Narathiwat to visit his father. The son had no symptoms while in Bangkok but got sick after returning to Narathiwat and tested positive for COVID-19.
His close contacts were then tested, and the father’s result came back positive for Beta. As of press time, lab tests had not yet confirmed if the other two infected relatives in Bangkok also caught Beta.
The father works in a Bangkok market. After his Beta infection was confirmed, tests on his co-workers all came back negative. Authorities now hope they can prevent local transmission of Beta in Bangkok, where the Alpha and Delta variants are spreading.
“For now, it is clear that Beta is still linked to the South,” Supakit said.
Beta overshadowed by Alpha, Delta
Although the spread of Beta needs to be monitored and controlled, medical experts are far more concerned about Alpha and Delta, because of their higher transmissibility.
First detected in the United Kingdom, the Alpha variant is 1.5 times more transmissible and carries a 1.5 times higher fatality rate. Thailand’s ongoing third wave, which has been far deadlier than the previous two, is being driven by the Alpha variant.
Alpha accounted for more than 80 per cent of COVID-19 cases in April. However, experts warn that the Delta variant is even more transmissible and on course to become Thailand’s dominant strain in a few months.
First detected in India, Delta accounted for 9.76 per cent of new infections in Thailand between June 6 and 13. The following week, that figure rose to 10.43 per cent and by June 20-27 it was 12.3 per cent.
Source: Thai Public Broadcasting Service (Thai PBS)