Already reeling from tourism-dominated economic debacle, Thailand is all set to resume its quarantine-free travel scheme from February 1.
The move came this week after the program was earlier suspended due to the fast-spreading Omicron variant of coronavirus.
Fully vaccinated travellers will now be able to enter under the "test and go" scheme as long as they take Covid tests on the first and fifth days after arriving, am official told reporters recently.
But what are the vaccines and mixes the Southeast Asian nation allowing?
Supply and availability issues for government-approved vaccines, together with worries about rare side-effects (such as thrombotic thrombocytopenia), have necessitated the switch to heterologous Covid vaccination schedules—an approach commonly known as mixing vaccines.
In early December, the Ministry of Interior had mandated that travellers must have two vaccine shots, with the exception of the Janssen vaccine by Johnson & Johnson that only requires one dose to be fully inoculated.
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Thai authorities then said they would will accept mix and match vaccine cocktails-- but determined exactly how much time should elapse between the two doses.
Any combination of vaccines must be completed at least 14 days before departing to travel to Thailand.
As of December 11, Thailand recognized eight vaccines as valid for entry into the kingdom, according The Phuket News. The vaccines are:
• AstraZeneca (Vaxzevria, Covishield)
• CoronaVac (Sinovac)
• Covaxin
• Covilo (Sinopharm)
• Janssen (Johnson & Johnson)
• Moderna
• Pfizer-BioNTech (Comirnaty)
• Sputnik V
For those that received a vaccine cocktail where two vaccines are mixed, the amount of time between doses that is accepted depends on which brand of vaccine they received:
• AstraZeneca – second dose after 4 weeks
• Covaxin – second dose after 4 weeks
• Moderna – second dose after 4 weeks
• Pfizer-BioNTech – second dose after 3 weeks
• Sinopharm: –second dose after 3 weeks
• Sinovac – second dose after 2 weeks
• Sputnik V – second dose after 3 weeks
WHO’s take on mixes
On December 16, the World Health Organization (WHO) issued interim recommendations for mixing and matching Covid-19 vaccines from different manufacturers for both the second dose and booster shots.
Depending on availability, mRNA vaccines, such as those developed by Pfizer and Moderna can be used as subsequent doses after initial doses of AstraZeneca's vectored vaccine and vice versa, it said.
AstraZeneca and any of the mRNA vaccines can also be used after initial doses of Sinopharm's inactivated vaccine, the global health body added.
Viral vector vaccines contain instructions for making coronavirus antigens, while mRNA vaccines use a code from SARS-CoV-2, the coronavirus that causes Covid-19, to prompt an immune response in recipients. Inactivated vaccines take the SARS-CoV-2 virus and inactivate or kill it using chemicals, heat or radiation.
The recommendation comes after a major study last week said a first dose of AstraZeneca or Pfizer/BioNTech shots followed by a Moderna vaccine nine weeks later induced a better immune response.
Many countries have already gone ahead with mixing and matching vaccines as they faced soaring Covid-19 infection numbers, low supplies and slow immunisation over some safety concerns.