The number of new confirmed cases soared to 4,914 last week, or 702 per day on average, ministry director-general Dr Opas Karnkawinpong said on Monday.
That figure is thought to be a small fraction of the true infection rate.
Patients severely ill with Covid currently number 553. Of these, 319 are on ventilators. Last week also saw an average 10 Covid-related deaths per day or 74 in total.
Infection rates were particularly high in Greater Bangkok and tourist provinces in the East and South.
The rate of infection is expected to rise in December and January, driven by dropping temperatures and gatherings during the festive period.
Opas said recent Covid-19 deaths came from first-time infections in mostly elderly or chronically ill people. Most victims were either unvaccinated, not fully vaccinated, or had not had a shot for more than three months.
Noting that protection after vaccination wanes over time, he urged people to get regular booster shots.
“Those who have not been vaccinated, please get a vaccine shot quickly. Those who got their last dose more than four months ago, please get another booster dose.
“Studies show that a booster or fourth dose reduces the severity and fatality of Covid-19. It will also strengthen your immunity for New Year festivities,” Opas said.
The ministry has ordered public hospitals in every province to open Covid vaccination centres and is coordinating to increase vaccination spots in Bangkok and tourism provinces, he added. Mobile vaccine services were being rolled out for elderly and bedridden people.
Opas said prevention measures – especially wearing face masks in public– were still important even after being vaccinated.
He also advised those aged 60-plus or with eight underlying health conditions to avoid eating with others or going unmasked in public if they have not been vaccinated in the last six months.
Anyone exposed to Covid hotspots in at-risk places or crowds should isolate from family members for five days and visit a hospital immediately if infected, he said.
Opas said Thailand had enough medicine, medical supplies and beds to treat moderate to severely ill Covid-19 patients.
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