Omicron cases likely undetected

BETTER TESTS NEEDED, SAYS VIROLOGIST

>>More than 30% of Covid-19 infections in Thailand are believed to be of the Omicron variant, says virologist Yong Poovorawan.

Dr Yong, of the Centre of Excellence in Clinical Virology at Chulalongkorn University, said that in every country, the reported number of Omicron infections is lower than the actual number due to a lack of variant identification efforts. “We must admit that the Omicron variant has been spreading in Thailand and other countries around the world,” he said.

To identify variants, genome analysis tests (S gene testing) must be conducted to verify the strain, he said.

Some countries use RT-PCR tests to detect Covid-19 infections. Dr Yong said S gene testing would more effectively detect Omicron infections, but it was not included in Thailand’s testing process, so it cannot be used.

Dr Yong said this led to about 3,000 cases reported in the media being inaccurate as many others have not yet been detected.

The centre is working with its limited capacity to detect the Omicron variant but it can only conduct tests in Bangkok and adjacent provinces, he said, adding the strain is believed to be widespread, and representing more than 30% of all infections.

Meanwhile, the Department of Disease Control (DDC) has indicated the Delta variant is still the dominant strain in Thailand and accounts for 70–80% of cases.

Despite the high transmission rate, Omicron symptoms do not appear as severe as those of Delta, it said.

A study indicated that patients, especially those who were vaccinated but still contracted the Omicron variant, should now have sufficient immunity to neutralise a Delta infection. However, the department does not recommend that people develop immunity by contracting the disease.

The DDC said most Omicron infections were asymptomatic, and the virus was mostly found in the windpipe.

The infected generally suffer from a cough, sore throat, fever, muscle pains, runny nose, headache, shortness of breath and temporary loss of smell, it said.

For the Delta, Alpha, Beta and original variants, patients will commonly experience fever, coughing, runny nose, sore throat, headache and shortness of breath, it said.

Other symptoms may include shivering, muscle pain, vomiting, diarrhoea, changes in the skin tone of fingers and toes, red eyes, rashes and temporary loss of smell or altered sense of taste.