One week before Songkran, Thailand's traditional new year in mid-April, health officials in Bangkok detected the presence of the coronavirus B117 first identified in Britain. This highly contagious variant was found in a cluster of patients who had visited entertainment venues in the capital.
To reduce the risk of it spreading, the government banned the splashing of water - an annual ritual - and cancelled all public events which might cause people to gather.
But, wary of the economic costs of a lockdown before the long holiday, it did not stop people from travelling back to their home provinces for family gatherings.
Provincial governors were left to impose their own health control measures.
The number of Covid-19 cases spiked after Songkran. On Monday (May 17), Thailand logged an all-time high of 9,635 new infections, over 70 per cent of whom were prisoners across the country.
On Tuesday, it reported 35 fatalities - another all-time daily high. The total number of cases hit 119,585 as of Thursday, with 703 deaths.
The "double mutant" B1617 variant of the virus first detected in India was also logged on May 10.
On Friday (May 21), a government spokesman announced that 15 workers had tested positive for the B16172 variant that was first identified in India and is prevalent in Singapore's current outbreak.
Professor Vip Viprakasit from Faculty of Medicine Siriraj Hospital at Mahidol University called the rising infections a "failure of the winner".
Speaking in his personal capacity, he noted that Thailand was hailed for its impressive performance during the first wave of the coronavirus last year.
At the end of November last year, the cumulative number of cases was still around 4,000, with 60 fatalities.
"However we kind of relaxed in terms of self-control, not just in policy but on a country-wide scale," the professor, who volunteers with the government's Covid-19 effort, told The Straits Times. "People became relaxed on personal hygiene measures, like wearing masks, using alcohol, and checking in. They had parties."
Added to these factors was a vaccination roll-out hampered by bureaucratic hurdles, he said.
"And such red tape led to a bottleneck," he said.
As of Wednesday, Thailand had fully vaccinated 819,961 people, less than 2 per cent of its population. Another 1.5 million people had received their first dose. Most are medical or other front-line workers who have received Sinovac, the Chinese vaccine.
Thailand's main vaccination programme will kick off only next month, after locally produced AstraZeneca vaccine doses are ready.
The government was criticised for placing most of its bets on the locally licensed vaccine instead of sourcing vaccines from a range of manufacturers. It also got flak for not joining the international Covax scheme aimed at ensuring equitable distribution of vaccines.
Under growing pressure, especially from the private sector, which wants to speed up the process, the Thai Food and Drug Administration (FDA) on May 13 granted emergency-use authorisation to the Moderna vaccine. This paves the way for private hospitals to provide the shots.
But there seems to be some hesitancy among the population to get inoculated. Beginning this month, anyone aged over 60 or suffering from conditions like cancer or diabetes can register in advance for vaccination.
As of Thursday, only 7.4 million of the 16 million in this priority group had signed up.
Prof Vip says Thailand needs a more sustained campaign to convince people that vaccines are safe.
One group which does not need convincing are the Americans in Thailand. While Thailand has said that foreigners in the country would be entitled to free vaccination, it has not said when this will take place.
On May 6, four American-led organisations, including Democrats Abroad Thailand, sent a letter to United States Secretary of State Antony Blinken urging the US government to vaccinate American citizens in Thailand.
Democrats Abroad Thailand chairman Paul Risley told ST that the costs of travelling back to the US to get vaccinated were prohibitive.
"This is a global pandemic, we can't stop Covid-19 until we can stop it in all countries; the sooner countries vaccinate their populations the better, before new variants emerge that might require new vaccines," he said.