The cumulative total of Covid-19 patients rose to 2,922.
Of the total, 2,594 have recovered while there have been 51 fatalities. Only 277 are still in hospitals, the first time the number is lower than 300, said Taweesin.
The 53 new cases on Saturday were the highest since April 9 when there were 54 new cases.
Over 18 days, new cases are clearly on a downward trend.
On April 9 there were 54 new cases, 50 on April 10, 45 on April 11, 33 on April 12, 28 on April 13, 34 on April 14, 30 on April 15, 29 on April 16 ,28 on April 17, 33 on April 18, 32 April 19, 27 on April 22, 19 on April 21,15 on April 22, 13 on April 23, 15 on April 24 , 53 on April 25 and 15 on April 26.
Taweensin, however, warned people in the 20-29 age group as at high risk for infection.
The new cases can be divided into three groups.
The first group of eight had close contact with four others previously confirmed as infected, three went to crowded areas, and one worked in a crowded area.
Two cases were detected during proactive efforts by health officials in Yala.
The last group of five people had returned from abroad -- four from the United Arab Emirates and one from the Netherlands.
Meanwhile, 47 people have fully recovered and returned home.
Of 15 new cases, seven were in Bangkok, four in Phuket, two in Yala, one in Chonburi’s state quarantine area, and one in Nakhon Pathom.
As of April 26, the total number of confirmed cases in the country stood at 2,922 -- 277 are under treatment while 2594 have recovered and been discharged, and there have been 51 deaths.
Globally, there are more than 2.89 million confirmed cases and over 200,000 deaths
On Sunday, a number of Thai people will return from overseas: 35 from Japan, 25 from the Netherlands, 207 from Australia, and 168 students from New Zealand.
Dr Taweesin said until a vaccine is developed and a cure found, people will need to cooperate with authorities and be vigilant to prevent the virus from spreading.