Daily recorded Covid-19 cases are expected to rise until the New Year due to a dip in temperatures and increased crowd gatherings, according to the Public Health Ministry.
Dr Opas Karnkawinpong, permanent secretary for public health, said on Monday that the infection rate of new Covid-19 cases increased last week.
He said the majority of the new cases involve the elderly and those with chronic diseases, including those who have not been fully vaccinated.
"Cases were mainly found in Bangkok, its neighbours, tourism provinces in the East and South," Dr Opas said.
"Senior citizens and people living with a chronic disease are still the majority of deaths, many of whom were infected for the first time."
Therefore, people are encouraged to still wear face masks in public spaces and get booster shots if their last vaccination was more than four months ago.
Dr Opas said there were 4,914 cases last week, including 553 people with lung infections and 319 who needed life support. The country is recording about 10 deaths per day on average, he said.
Dr Supakij Sirilak, director-general of the Department of Medical Sciences, said 58% of recent patients were infected by the Omicron BA.2.75 subvariant, which was spreading rapidly.
He said that in his opinion, it might be possible to detect cases involving the XBB subvariant as foreign tourists return to the kingdom for the holiday season.
"Vaccines can save your life. If your latest shot was more than four months ago, please come to get one more to boost immunity against the disease," he said.
"We must urgently increase our immunity levels before the New Year festival to ensure people will be free from infections," he said.
Yong Poovorawan, director of the Center of Excellence in Clinical Virology at the Faculty of Medicine, Chulalongkorn University, predicted on Facebook on Monday that a new outbreak will not be as severe as those in the past given increased immunity among the public due to vaccines.