askST: What are possible side effects from Covid-19 vaccine?

A senior staff nurse preparing the vaccination for his fellow healthcare workers at NCID in Singapore, on Dec 30, 2020. ST PHOTO: KEVIN LIM

SINGAPORE - Vaccinations against Covid-19 began on Wednesday (Dec 30) with the first Pfizer-BioNTech jabs administered to 40 healthcare workers at the National Centre for Infectious Diseases (NCID).

The Straits Times answers some of the questions that have arisen about the vaccine.

Q: Will front-line and essential workers be allowed to stay in their posts if they decline the injection?

A: Although vaccination of healthcare workers is not compulsory, all local residents - healthcare workers and the general public - are urged to take the jab.

There is no plan to alter the duties of healthcare workers who do not get vaccinated, said NCID executive director Leo Yee Sin. Hospitals also continue to comply with preventive measures.

Q: What precautions need to be taken after the injection? Do patients wait to ensure they do not have side effects?

A: The Covid-19 vaccination is no different from other vaccinations, said Prof Leo, adding: "It is recommended by the Health Sciences Authority to observe the vaccinees for 15 to 30 minutes after vaccination."

There are resting spaces in full sight of healthcare workers for patients who have completed their vaccination.

Q: How do we know the vaccination is working? Some people have no observable reactions, while others might have a mild or severe one.

A: There is no evidence to suggest that those with no or mild discomfort are not protected by the vaccine.

The safety profile of the Pfizer-BioNTech vaccine is generally consistent with other vaccines used against other diseases, said Prof Leo, who was vaccinated on Wednesday.

Some people may have side effects like pain, redness, swelling at the injection site. Other side effects include fatigue, fever, headaches, muscle aches, chills, vomiting, diarrhoea and joint pain.

While not everyone will experience these, they are common and expected as part of the body's natural response, so as to build immunity against Covid-19. These side effects are also usually resolved within a few days.

As with other vaccines, in rare cases, a person may experience severe allergic reactions, such as difficulty in breathing, wheezing and swelling around the eyes and lips. Immediate medical attention must be sought. Anyone with a history of anaphylaxis should also not receive the Pfizer-BioNTech vaccine.

Q: Will the vaccination leave a keloid scar like the Bacillus Calmette-Guérin (BCG) vaccine?

A: It is unlikely as this is intra-muscular injection (like the influenza vaccine). There have been no reports of scarring. The BCG is a live attenuated vaccine - a vaccine created by reducing the virulence of a pathogen.

Q: How is the vaccine kept viable?

A: The NCID works closely with the Health Ministry to hold just enough doses before they are to go to vaccination providers. Vaccines can be stored at a temperature of 2-8 deg C for up to five days.

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