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Updated 16 Oct 2021

General Information on COVID-19 Vaccines


Who is the booster dose for?


The following persons are recommended to receive a booster dose of a PSAR mRNA vaccine, from about six months after completion of their primary series:

a. Persons aged 30 years and above
b. Residents of aged care facilities*
c. Healthcare and frontline workers*
d. Persons and staff in institutionalised settings*

*Aged 18 years and above

Why is there a need for a booster dose?

While the primary series of the recommended COVID-19 vaccines provides good protection against severe disease, protection against infection could decrease over time. An increased risk of vaccine-breakthrough infections has been observed locally. Booster vaccination is therefore needed to reduce the risk of COVID-19 infection and transmission.

 If I have recovered from COVID-19, and have been vaccinated, do I still need to take the booster dose?

At present, persons who have recovered from COVID-19 and were fully vaccinated before their infection, do not need a booster dose.

Recovered persons who were unvaccinated, or partially vaccinated before their infection, should receive one dose of mRNA vaccine at least 3 months after infection to reduce their risk of reinfection, as part of their primary series vaccination. No additional booster dose is recommended at this time.


Are there any safety concerns if I had unknowingly recovered from COVID-19 but take the booster dose?


There are no additional safety concerns with taking the booster vaccination if you had unknowingly recovered from a past infection. There is no known evidence that the vaccination of recovered persons causes over-stimulation, autoimmune disorders or other safety concerns.

  When and how can I register for my booster dose?

The booster dose is recommended to be taken from about six months after you have been vaccinated with two doses.

Eligible persons for their booster dose will be progressively invited to receive the vaccination. An SMS with a personalised booking link will be sent to the mobile number that you had registered with for your first two doses. Please use it to book an appointment for the booster on 

Eligible seniors aged 60 years and above who have met the recommended window of about six months after their second dose, will also be able to walk into any Vaccination Centre, or participating Public Health Preparedness Clinic (PHPC) without a prior appointment to receive their booster dose.

 Does my booster dose have to be of the same brand as my first 2 doses?
A: Your booster dose can be of either brand of the Pandemic Special Access Route (PSAR) mRNA vaccine.


Persons who are immunocompromised are already required to receive 3 doses as part of the primary series. Do they need to receive a booster as well?


Persons who are immunocompromised and have received a 3-dose enhanced primary series are recommended to receive a booster dose of a PSAR mRNA vaccine, six months after the completion of their 3-dose enhanced primary series if they also belong to the groups recommended to receive a booster dose.

 If I received two doses of Sinovac/Sinopharm, is it still recommended for me to receive the third dose?

Persons who had received two doses of Sinovac/Sinopharm under HSA's Special Access Route are recommended to receive a dose of the PSAR mRNA vaccine as a booster dose, if they are not contraindicated to receive the mRNA vaccines.

  Will individuals below the age of 30 be offered the booster dose?

Persons in the general population* below the age of 30 years are currently not yet recommended to receive booster dose. MOH and EC19V will continue to monitor data on this and update the recommendations for this group of persons as necessary.

*Except healthcare workers, frontline workers or persons belonging to institutional settings, who are at high risk of infection. They are recommended to receive the booster vaccination if they are 18 years and above.

 [Updated 16 Oct] Will the booster dose affect my vaccination status?

Persons with two doses of mRNA vaccines are considered “fully vaccinated” for the purpose of vaccine differentiated safe management measures (SMMs). While not receiving the additional dose will not affect your vaccination status, the booster is highly recommended as it increases your body’s ability to develop a more protective immune response to reduce your risk of suffering severe COVID-19.

If your vaccination status is not accurately reflected, you may raise your query at

 Is a third dose safe?

Yes, the EC19V has assessed that the benefits of another dose of the vaccine outweigh the risks for the recommended groups. There is now good international data that a booster dose of the vaccine is safe, enhances protection against COVID-19 infection and ensures continued excellent protection against severe disease.

Most side effects are mild or moderate, and usually get better within a few days.  As with all vaccines and medications, there is a small risk of serious adverse events. Countries which have been providing booster doses have not reported any safety concerns.

 What is the dosage used for booster vaccination?
 A:The dosages for booster vaccination by vaccine types are:

• 50 mcg for the Moderna vaccine
• 30 mcg for the Pfizer-BioNTech/Comirnaty vaccine

The booster dosage of the Moderna vaccine is less than the 100 mcg used for the first two doses. This is because data has shown that a 50 mcg dose effectively boosts the immune protection against COVID-19. If you have received a 100 mcg dose for your booster vaccination, there are no safety concerns in having done so.

The booster dosage of the Pfizer-BioNTech/Comirnaty vaccine is the same as that used for the first two doses.

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