For more popular FAQs, click here.

Click Ctrl+F (On Windows) or Cmd+F (On Mac) to look for word of interest, or find latest FAQs on top of each section.
Updated as of 8 Jul 2022

General Information on COVID-19 Vaccines


How many types of Covid-19 vaccines are there?


There are 5 main types of COVID-19 vaccines which have been announced:  


a.  mRNA vaccines: e.g. Pfizer-BioNTech/ Comirnaty, Moderna, Arcturus

b.  virus vectored vaccines: e.g. Astra-Zeneca, Gamaleya, Can-Sino

c.  inactivated virus vaccines: e.g. Sinovac, Bharat

d.  protein subunit vaccines: e.g. Novavax, Sanofi-Pasteur

e.  virus-like particle (VLP) vaccines: e.g. Medicago

How do mRNA vaccines work?


The COVID-19 mRNA vaccine consists of messenger ribonucleic acid (mRNA) that carry instructions to make the spike protein of the virus. The mRNA used in the vaccine is synthesised and not extracted from actual viruses. After being given by intramuscular injection, the vaccine mRNA is taken up by cells which then produce the spike protein. This stimulates the production of a good antibody and cellular immune response to the spike protein that protects the vaccinated person because the spike protein is an important part of the SARS CoV-2 virus. The spike proteins are however incapable of forming SARS CoV-2 viruses or causing COVID-19 infection. The vaccine mRNA only persists for two days before it is naturally broken down by the body. It does not enter the nucleus of cells and hence cannot interfere with the DNA of the vaccine recipient.


Are mRNA vaccines a form of genetic modification?


No, they are not a form of genetic modification. The mRNA vaccine is in a form that is cannot be converted back to DNA. Since our human genome is made up of DNA, there is no possibility that the COVID-19 mRNA will interfere with or modify human DNA. The mRNA is completely degraded within 48 hours of introduction to the human body.


The spike protein generated through the introduction of the COVID-19 mRNA is recognised by the body’s immune system to develop an immune response (e.g. generation of antibodies), similar to what happens in a natural infection against COVID-19.


Are the COVID-19 vaccines halal?


The Islamic Religious Council of Singapore (MUIS)’s position is that COVID-19 vaccines are permissible for Muslim use. Please refer to MUIS’ religious position on the COVID-19 vaccine here.

 What is the Comirnaty vaccine? Is it the same as Pfizer-BioNTech?
A: Yes, they are the same. The Comirnaty COVID-19 vaccine is the same as the Pfizer-BioNTech COVID-19 vaccine that we have been using in our national vaccination programme. The only difference is in labelling. 

The Pfizer-BioNTech vaccine is manufactured at various sites across Europe and labelled according to the regulatory approval in various markets. Both Pfizer-BioNTech and Comirnaty have the same research name - BNT162b2, and are manufactured according to the same processes and procedures. They are similarly manufactured in Europe and shipped directly to Singapore.

Those who received the Pfizer-BioNTech vaccines earlier will see that their records in Health Hub / TraceTogether now reflect PfizerBioNTech/ Comirnaty. 

I understand that there may be more than one strain of COVID-19. Will the vaccine cover us fully against all strains?


Based on Phase 3 trial data from Pfizer-BioNTech/Comirnaty and Moderna, the efficacy of vaccines in preventing symptomatic COVID-19 disease from the initial SARS-CoV-2 strain, after completion of the vaccine regimen, is above 90%. Locally, against the Delta variant, they have been found to reduce the risk of any infection by around 40%, while the risk of severe disease is reduced by around 90%, in the absence of boosting. 

There is limited data on the efficacy and effectiveness of the Sinovac-CoronaVac vaccine against the Delta or the Omicron variant. 
MOH will continue to monitor the evolving situation and global studies of vaccine efficacy against various COVID-19 variants.

 [Updated 8 Jul] Who should receive a booster?

Individuals aged 12 years and older are recommended to receive a booster dose from about five months after the last dose of their primary vaccination series*, or as soon as possible thereafter, in order to maintain good protection against COVID-19.

Persons who had recovered from COVID-19 and completed the recommended COVID-19 primary vaccination are similarly recommended to receive a booster dose. This should also be from about five months after the last dose of their primary vaccination series and should be received at least 28 days after the infection, although they are recommended to do so three months from the infection for better effectiveness.

Individuals aged 12-17 years are recommended to receive a booster dose of a Pfizer-BioNTech/Comirnaty vaccine, while individuals aged 18 years and older are recommended to receive a booster dose of either the Pfizer-BioNTech/Comirnaty vaccine or the Moderna/Spikevax vaccine- under the National Vaccination Programme.

For those who received the Sinovac-CoronaVac vaccine as their third vaccine dose as part of a three-dose primary vaccination series incorporating the Sinovac-CoronaVac vaccines, they should receive a booster dose of a mRNA vaccine under the National Vaccination Programme earlier - from three months after the third dose of the vaccine, due to lower antibody levels generated by the third vaccine dose.

This booster dose should not be delayed beyond nine months after the primary vaccine course.

*The primary vaccine course may comprise of either:

·       Two doses of either the Pfizer-BioNTech/Comirnaty, Moderna/Spikevax or the Novavax/Nuvaxovid COVID-19 vaccine;
·       Two or more doses of the Sinovac-CoronaVac vaccines as part of a three-dose primary vaccination series; or
·       A complete primary vaccination regimen of other WHO EUL vaccines.



Booster recommended?


Completed 2 doses of mRNA or Novavax/Nuvaxovid vaccines



Completed 3 doses of Sinovac-CoronaVac



Completed primary series regimen of other WHO EUL vaccines:

· Completed 1 dose of Johnson & Johnson

· Completed 2 doses of AstraZeneca, Covishield, Covaxin, Novavax

· Completed 3 doses of Sinopharm



Fully vaccinated persons, who have previously recovered from infection


Note: Recommendations for Sinovac-CoronaVac will apply to Sinopharm as well.
 [Updated 8 Jul] I tested positive on self-administered ART and have yet to complete my COVID-19 primary vaccination series. When can I take my next dose?
 You should proceed to complete your vaccination. It is safe for you to receive two doses of mRNA vaccines for the primary vaccination series, and you are also recommended to receive one dose of the mRNA vaccine as a booster. If you are not medically eligible for the mRNA vaccines, you should complete your vaccination using alternative vaccines (e.g. Novavax/Nuvaxovid, Sinovac).

If you are due for your vaccination based on the schedules recommended in the national vaccination programme (e.g. to receive a booster dose about 5 months after two doses of mRNA vaccines), you may receive your next vaccine dose from 28 days after the infection, although you are recommended to do so three months from the infection for better effectiveness.

Click the back button on your browser or click here for the main page on FAQs.