A second batch of Pfizer Covid-19 vaccines for healthcare professionals in 77 provinces is expected to arrive on Saturday, according to the Department of Disease Control (DDC).
Opas Karnkawinpong, the department's director-general, said 257,200 doses of the US-made vaccine should arrive in the provinces no later than tomorrow.
He said a total of 700,000 doses had been distributed with the first batch of 442,800 doses delivered last Wednesday and Thursday.
Dr Opas said the delivery was divided into two batches one week apart for a number of reasons.
Some provinces submitted their requests after the July 30 deadline while other requests did not match the number of Sinovac recipients in the database.
The Pfizer vaccines, donated by the US government, will be administered as boosters to medical personnel and frontline workers who have already received two shots.
The US government last month donated a total of 1,503,450 doses of Pfizer vaccine to Thailand to help the country's fight against Covid-19.
Dr Opas said the vaccine allotment is based on the Public Health Ministry's database, MOPH-IC, for vaccinations between Feb 28-June 22. At the beginning of the vaccine rollout, medical personnel, both frontline and support groups, received two shots of Sinovac.
"The delivery of vaccines to large hospitals and medical schools started on Aug 8 and they should arrive there no later than Aug 14. The DDC has also attached a document showing the allotment of 700,000 doses of the Pfizer vaccine in the shipment," he said.
He insisted the department had not hoarded the vaccine for VIPs and urged people who have information about any mishandling of the inoculations to contact the Public Health Ministry.