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Doctor Answers 10 Questions about COVID-19 Vaccine

There are many questions about the COVID-19 vaccines that are available in Singapore, especially with two currently approved by Ministry of Health (MOH). Here are the 10 most asked questions about COVID-19 vaccines in Singapore:

1. Which is better, Moderna or Pfzier?

Both COVID-19 vaccines work similarly and both vaccines employ the same novel messenger RNA (mRNA) technology. They both have a similar eligibility criteria, efficacy of over 90% (Pfizer 95% vs Moderna 94.1%) and side effect profile. It is not so important to choose one over the other, but to get vaccinated as soon as possible. 

2. If having side effects mean the immune system is functioning, what happens if I don’t have any symptoms?

Everyone reacts differently to the COVID-19 vaccine and may have different threshold for discomfort. Even if you have no symptoms, it is still likely that your immune system is functioning as desired and building protection against COVID-19.

3. I have a history of multiple drug allergies/ facial swelling, is it still safe for me to take the vaccine?

Yes, as long as you do not have a severe allergic reaction such as anaphylaxis or a severe drug reaction, it is still recommended you take the COVID-19 vaccine even if you have multiple drug allergies.

4. Can I still get infected with COVID-19 after the vaccine?

No vaccine is 100% effective. The Pfizer and Moderna COVID-19 vaccines are considered very effective at 95% and 94.1% effectiveness respectively. That means about 1 in 20 may not be immune to the virus. However from the trials and our experience in Singapore, we also know those who have contracted COVID-19 after vaccination usually have milder course of illness.

This is also why it is important to keep to the safe management measures and practise good hygiene.

5. Is there any food I should avoid after the COVID-19 vaccine?

It is recommended that alcohol is held off for 24 hours after vaccination. There are otherwise no food groups that you should avoid as long as you did not have any previous allergy to it. If you do have an allergy to a certain food, say prawns, you should abstain from prawns for the next 1 week so as not to confuse allergy to food with allergy to the vaccine.

6. I have many chronic conditions like high blood pressure, diabetes and high cholesterol, can I still take the COVID-19 vaccine?

Unless the medical condition is in the list of contraindicated conditions such as active cancer on treatment or severely immunocompromised, even if you are on multiple medications for multiple chronic medical conditions, there is no contraindication to take the vaccine. 

In fact, those who have multiple chronic conditions are strongly recommended to take the vaccine as they are considered to have less reserves and more likely to suffer complications from a COVID-19 infection. 

7. Should I stop all my medication before the  vaccine?

No, there is no need to stop your medication before the COVID-19 vaccine. Please continue to take your chronic medication as per normal.

8. What medication can I take for the side effects from the COVID-19 vaccine?

Common side effects include fever, body aches, pain or swelling at the site of injection. You can take over the counter paracetamol for these side effects. Try not to take non steroidal anti-inflammatory drugs (NSAIDS), such as diclofenac, ponstan or arcoxia, for your aches.

9. Does the COVID-19 vaccine affect fertility?

There is no evidence that the Pfizer or Moderna COVID-19 vaccines affect fertility. 

However ladies should defer trying to conceive until 1 month after the 2nd dose of their vaccine. If you become pregnant between the first and second dose, you should defer the second dose till after delivery.

10. Why must we be observed for 30 minutes after vaccination?

Most severe cases of allergic reaction happen in the first 15 minutes after the vaccination. In an abundance of caution, MOH mandates a 30 minute observation period at the vaccination centre where a doctor is on standby to attend to any medical emergencies post vaccination.

For more information about the COVID-19 Vaccination, please visit MOH website

Dr Jiayi Wong

M.B.B.S (Singapore) Bachelor of Medicine | Bachelor of Surgery

Started as a general practitioner in one of Minmed's clinic, Dr Wong is constantly looking for more challenges and ways to contribute as a medical professional.

Dr Wong now overlooks the medical protocols of the group while leading a team of doctors and nurses at Minmed's COVID-19 vaccination centres, mobile vaccination teams and COVID-19 testing operations.

A father of 3, his jovial nature never fails to cheer up those around him.