COVID-19 Vaccines

What is a COVID-19 vaccine?

A COVID‑19 vaccine provides acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus that causes coronavirus disease 2019 (COVID-19).

Types of COVID-19 vaccines

There are 5 main types of COVID-19 vaccines:

1. Messenger RNA (mRNA) vaccines, such as Moderna/Spikevax and Pfizer-BioNTech (Comirnaty). mRNA vaccines contain material from the COVID-19 virus that instructs our cells to produce a protein that is unique to the virus. After our cells make copies of the protein, they destroy the genetic material from the vaccine. Our bodies recognise that the protein should not be present and work to produce antibodies to attack the virus.
2. Inactivated whole virus vaccines, such as Sinovac and Sinopharm. These vaccines use weakened or inactive viral particles to stimulate our body to produce antibodies that will help neutralise the COVID-19 virus. Parkway Shenton clinics offer the Sinopharm vaccine. You may choose to take the Sinopharm vaccine as part of your primary series vaccination or as a booster dose.
3. Viral vector vaccines, such as Oxford AstraZeneca, Johnson & Johnson, CanSino and Sputnik V. These vaccines use a modified harmless virus to induce your cells to make viral proteins. Your body’s immune system then mounts a defence against it.
4. Protein subunit vaccines, such as Novavax. These vaccines use specific parts of the virus only, which is enough to trigger an immune response.
5. Bivalent vaccines, such as the Pfizer-BioNTech/Comirnaty bivalent COVID-19 booster vaccine and the bivalent Moderna/Spikevax vaccine. These vaccines offer protection against 2 different variants of the COVID-19 virus – the original SARS-CoV-2 virus, and the Omicron variant(s). Compared with the original mRNA vaccines, these new bivalent COVID-19 vaccines also offer added protection against newer COVID-19 variants, including XBB.

Why do you need a COVID-19 vaccine?

COVID-19 is a highly contagious disease that can cause severe illness and death, especially among the elderly and other vulnerable persons (e.g. persons with 2 or more illnesses, or women who are pregnant).

Vaccination protects you and your loved ones from getting seriously ill or dying from a COVID-19 infection. Vaccination also helps to lower the risk of transmission and prevent Singapore's healthcare system from being overwhelmed.

Who should not take a COVID-19 vaccine?

COVID-19 vaccination is not recommended under these conditions:

• You have a history of allergic reactions of anaphylaxis to a COVID-19 vaccine or its components. Anaphylaxis is a severe, life-threatening reaction that includes 2 or more of these criteria:
  • Hives or swelling of the face, eyelid, lip or throat
  • Difficulty breathing
  • Dizziness
• You are severely immunocompromised. Although it is still possible for you to take a COVID-19 vaccine, please consult your doctor on your suitability and appropriate windows to be vaccinated if you:
  • Have had a transplant within the past 3 months
  • Are receiving treatment for cancer that is active
  • Are undergoing aggressive immunotherapy

What are the risks and complications of taking COVID-19 vaccines?

COVID-19 vaccines are safe for the general population. Very rare complications include:

• Myocarditis (inflammation of the heart muscle)
• Pericarditis (inflammation of the membrane surrounding the heart)

These adverse events have been reported following the second dose of mRNA COVID-19 vaccines and were mostly reported in younger men aged 12 – 29 (40.6 cases of myocarditis per million second doses).

Serious side effects to COVID-19 vaccines are rare and may include anaphylaxis, which is a severe and potentially life-threatening allergic response. Anaphylaxis may involve hives or swelling of the face, eyelid, lip or throat, difficulty breathing or dizziness.

How do you prepare for a COVID-19 vaccination?

On the day of the vaccination, wear short-sleeved attire, or sleeves loose enough to be rolled up.

If you are unwell or had a fever in the past 24 hours, please stay home and postpone your vaccination till you recover.

What can you expect when you receive a COVID-19 vaccination?

You may experience some side effects from the vaccine, which are normal signs that your body is responding to the vaccine. If you are taking the Sinopharm vaccine:

• The first 2 doses are administered with an interval of 3 – 4 weeks.
• You should take your third dose 90 days after your second dose.

Before the procedure

There will be a round of medical screening conducted on-site to check your eligibility for the vaccine. To be eligible for the Sinopharm vaccine, you should:

• Be at least 18 years old.
• Not have had allergic reactions to vaccines previously.
• Not have any known allergies (including anaphylaxis) to any components of the vaccine.
• Not have uncontrolled epilepsy or other progressive nervous system diseases, nor a history of Guillain-Barre syndrome.
• Consult your obstetrician to assess your suitability for the vaccine if you are pregnant.

During the procedure

The vaccine is administered via an injection into your arm. The process is quick and relatively painless.

After the procedure

You will be observed for approximately 30 minutes after your vaccination. Should you develop any adverse reactions to the vaccine, please alert your care team immediately.

Some people will experience mild to moderate side effects hours after receiving COVID-19 vaccines. Common side effects include:

• Pain or redness at the injection site
• Muscle ache
• Tiredness
• Headache
• Chills
• Fever

Not everyone will experience side effects. Most side effects go away on their own within a few days.

Care and recovery after a COVID-19 vaccination

If you experience side effects such as fever, tiredness or muscle aches, you should:

• Rest well
• Avoid strenuous activities
• Take medication to relieve fever and pain, if necessary

Mild side effects usually resolve on their own after a few days.