No Covid-19 infections were found among 1,603 tested people who were in places visited by an infected Egyptian serviceman in Rayong and an infected daughter of a Sudanese diplomat in Bangkok.
In Rayong, 1,336 people underwent coronavirus tests on Tuesday and all tested negative, Suwannachai Wattanayingcharoenchai, director-general of the Department of Disease Control, said yesterday.
They had either been at the hotel where the infected air force official had stayed, or one of the shopping malls he and other Egyptian servicemen visited, Dr Suwannachai said.
In Bangkok, 267 people who thought they could be at risk were also tested on Tuesday. None were infected, he said.
Most lived at the One X condominium building in the Sukhumvit area where the Sudanese attache's family stayed after arriving from Khartoum. His young daughter later tested positive for Covid-19.
On Wednesday, samples were taken from another 1,252 people in Rayong. They were awaiting the results, the doctor said.
Although lab tests on the 1,603 came back negative, these people should continue to wear face masks, frequently wash their hands, observe social distancing and avoid going out for 14 days, Dr Suwannachai said.
Taweesilp Visanuyothin, spokesman of the Centre for Covid-19 Situation Administration (CCSA), said yesterday the Sudanese girl's case involved six people who were at high risk of infection -- five family members and an embassy driver -- while 16 people living at the condo building, and two Foreign Ministry officials were thought to be low risk.
In the Egyptian Covid-19 case, 12 people were thought to be at high risk of infection, including a taxi driver who talked to the infected soldier for five minutes.
People at low risk included 885 visitors to Passione Shopping Destination mall which the infected serviceman and most of his colleagues visited and 447 people who went to CentralPlaza Rayong where other members of the Egyptian group went.
Meanwhile, the CCSA yesterday reported four new Covid-19 cases among quarantined returnees from the United Arab Emirates, Egypt and the United States.
Dr Taweesilp announced the latest figures and also issued a warning.
"Regarding the critical global situation, we can no longer expect Thailand to be free of new Covid-19 cases. But we must limit the number," Dr Taweesilp said.
He said two of the new patients had returned from the UAE. One was a 33-year-old male worker and the other a 25-year-old masseuse.
They arrived back on July 2 and were quarantined in Chon Buri province. They tested positive for Covid-19 on Monday, but showed no symptoms.
The third new case was a male student, 27, who arrived from Egypt on July 8. He had been in close contact with a Covid-19 patient in Egypt and was quarantined in Chon Buri. He tested positive last Saturday, but showed no symptoms.
The fourth was a woman aged 51 who returned from the US last Saturday and was quarantined in Bangkok.
Last Friday she had a fever, headache and had lost her sense of smell. She had been in close contact with a Covid-19 patient in the US. She tested positive on Wednesday, Dr Taweesilp said.