There was no infection found among the 1,603 people tested for Covid-19 after being in places visited by an infected Egyptian soldier in Rayong and the infected young daughter of a diplomat in Bangkok.
In Rayong, 1,336 people underwent coronavirus tests on Tuesday. They had been at the hotel where the infected Egyptian stayed, or at one of the shopping malls he visited, Suwannachai Wattanayingcharoenchai, chief of the Disease Control Department, said on Thursday.
All tested negative, Dr Suwannachai said.
In Bangkok, 267 people who thought they may be at risk were tested on Tuesday. None were infected.
Most lived at the One X condominium building in Sukhumvit area where the Sudanese attache's family stayed after arriving from Khartoum. The 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, he said.
Although lab tests 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, said on Thursday the Sudanese girl's case involved six people who were at high risk of infection - five family members and and an embassy driver - and 18 others who were at low risk - 16 people living at the condominium building, and two foreign affairs officials.
In the Egyptian Covid-19 case in Rayong province, 12 people were at high risk of infection, including a taxi driver who talked with the infected soldier for five minutes.
People facing a low risk included 885 visitors to Passione Shopping Destination mall and 447 people who went to CentralPlaza Rayong.
Results were back from tests on a total of 1,603 people in Rayong and Bangkok and all were free of the disease, Dr Taweesilp confirmed.