The Delta variant is responsible for 70% of people in Bangkok falling sick with Covid-19, says a study by the Centre of Excellence in Clinical Virology at Chulalongkorn University.
The findings were revealed by Yong Poovorawan, the centre director, on his Facebook page.
He said the first outbreak of Covid-19 came early last year with the Wuhan strain, which quickly spread around the world.
The strain returned in a second outbreak late last year with a hotspot identified at a central shrimp market in Samut Sakhon. The virus was thought to have come from Myanmar.
The current third outbreak has been dominated by the Alpha (UK) variant which transmits 1.7 times fast than the Wuhan strain, said Dr Yong.
The first cluster during the third outbreak of infections was centred on the upscale entertainment district of Thong Lor. The Alpha variant is believed to have spread from Cambodia.
As the current outbreak persists, the Delta (Indian) variant is steadily making inroads. It is 1.4 times more transmissible than the Alpha strain.
The centre has run research on more than 700 Covid-19 cases in Bangkok, which confirmed the rapid transmissibility. The study also shows that 70% of subjects were infected with the Delta variant, and it is not always possible to tell where people caught the virus. The study predicts the Delta variant is set to surge -- especially in the capital.
Supakit Sirilak, director-general of the Department of Medical Sciences (DoMS), said Delta-variant infections were on the rise.
According to the department's most recent figures, released on June 28, Alpha remained the dominant variant, accounting for 80% of infections, followed by the Delta strain (16.5%) and Beta (South African) variant (3.2%). The next update is set for Sunday.
Meanwhile, 41 Covid-19 deaths and 6,230 new cases were reported on Saturday, bringing the accumulated toll to 2,182 fatalities and 277,151 cases since the start of the pandemic. Of the new infections, 5,936 were among the public and 294 were found in prisons.
Since April 1, when the third Covid wave began, there have been 248,288 patients, 190,073 of whom have recovered. Since the pandemic started early last year, there have been 277,151 cases, 217,499 of whom have recovered.
The death toll has reached 2,088 in the third wave and stands at 2,182 from the beginning of the pandemic early last year. In the past 24 hours, 3,159 patients were discharged from hospitals.
The 41 new fatalities, 21 of whom were men, were 30-88 years old, with an average age of 66. All were Thais, the Centre for Covid-19 Situation Administration (CCSA) said in its afternoon briefing. Thirty of those who died had hypertension and 23 had diabetes. Fourteen caught the virus from family members.
Twenty-nine of the new fatalities were in Bangkok, while the rest were reported in surrounding provinces (3), the South (2), other provinces (6) and one in a prison. The 6,230 new cases over the past 24 hours comprised 6,226 local infections and four imported cases. Of the local infections, 4,412 were confirmed at hospitals, 1,520 via mass testing and 294 at prisons.
Bangkok again logged the most new cases at 1,971, followed by 479 in Samut Prakan, 448 in Pathum Thani, 294 in Chon Buri, 277 in Samut Sakhon, 257 in Nonthaburi, 197 in Pattani, 172 in Songkhla, 169 in Nakhon Pathom and 159 in Yala.
