The antigen test kits (ATKs) used on students and teachers at a school in Mukdahan, where all the test results were later proven to be false positives, had not been approved for use by the Food and Drug Administration (FDA).
Deputy FDA secretary-general Surachok Tangwiwat said on Saturday that a check by the FDA found the ATKs are of the Dvot brand and were donated to the school.
"However, they were not approved for use by the FDA," he said.
In light of this case, Dr Surachok urged all agencies and the public to make sure they choose approved ATKs for use in Covid-19 screening of their personnel. Initially a false alarm was suspected when antigen tests kits returned positive results at Kham Soi Phitthayasan School in Mukdahan's Nikhom Kham Soi district, but further RT-PCR tests all proved negative.
According to the Department of Disease Control, 14 teachers and three students initially tested positive using ATKs procured by the school on Thursday.
Provincial public health officials then carried out rapid antigen tests on a further 1,106 students and school personnel and 87 of the results came back positive.
However, Tharit Prasarnsorn, the Education Ministry's inspector-general, said all the tests had since been proven to be false positives. Nevertheless, the school has been ordered closed for 10 days with classes to continue online, Mr Tharit said.
Meanwhile, government spokesman Thanakorn Wangboonkongchana said yesterday that about 3.11 million students aged 12 and older, or 80.65% of the total nationwide, have now received at least one dose of Covid-19 vaccine.
According to the Department of Disease Control, of the 3.85 million students aged 12-18 who had registered for vaccinations, about 2.5 million students have received their first jabs and 600,000 have got the second shots.