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Updated  8 July 2022

Safety and Efficacy of the COVID-19 Vaccine

 Do the current COVID-19 vaccines protect against the Omicron variant?
 
The current COVID-19 vaccines still offer a high level of protection against severe illness even with the Omicron variant.
 Should I still be vaccinated with the current COVID-19 vaccines or should I wait for a vaccine that targets the Omicron variant?
 

The current COVID-19 vaccines still offer a high level of protection against severe illness even with the Omicron variant. Getting vaccinated now and receiving the booster as recommended will reduce your risks of getting infected and developing severe disease in the current situation.

Vaccines for the Omicron variant are still in under development and unavailable.
  Is there a higher risk of side effects from the third or fourth doses of mRNA vaccine as compared to the first two doses? What are the common side effects of the third and fourth doses?
 There is currently no indication that the third dose or fourth dose of an mRNA vaccine has a higher risk of side effects as compared to earlier dose(s). Common side effects included injection site pain, fatigue, headaches, muscle and joint pains, and chills. Most side effects are mild or moderate, and usually get better within a few days. There have not been any safety concerns with the third or fourth dose.
 

Which vaccines are approved for use in Singapore? Which of these vaccines are included in the national vaccination programme?

A:The Health Sciences Authority (HSA) has assessed that the Pfizer-BioNTech/ Comirnaty, Moderna/Spikevax, Novavax/Nuvaxovid and Sinovac-CoronaVac COVID-19 Vaccines meet safety and efficacy standards.

The Expert Committee on COVID-19 Vaccination (EC19V) has also recommended the use of the Pfizer-BioNTech/ Comirnaty, Moderna/Spikevax and Novavax/Nuvaxovid COVID-19 Vaccines by the majority of the population, and the use of Sinovac-CoronaVac by persons who are medically ineligible to receive the other vaccines. These vaccines are offered under the national vaccination programme. All are currently available in Singapore. Only vaccines deemed suitable for use in target population subgroups, and where overall benefits outweigh the known risks, are recommended for use by the Expert Committee.

Vaccines for COVID-19 have been approved for use in a shortened timeframe compared to other vaccines or drugs. How can we be sure that scientific rigour has not been compromised?

A:

An accelerated development timeline for vaccines against COVID-19 was possible given the following:

 

a. Significant investment and dedication of resources from vaccine manufacturers to the ramping up of vaccine production;

b. The mRNA technology platform had already been in development for many years prior to the COVID-19 pandemic.

 

c. Strong global partnerships between many different partners including international organisations, governments, researchers and manufacturers;

 

d. Given the pandemic situation, recruitment for and conduct of the randomised controlled trials to identify the differences in disease risk between those given vaccines and placebo, are able to be conducted more quickly than in the absence of a pandemic.

 

e. Many trials have performed their trial phases concurrently, allowing for sufficient data to be produced in a shorter time.

 

Safety, scientific or ethical integrity have not been compromised, and no short-cuts have been made, but the unique circumstances and factors described above have allowed accelerated development.

 

Emerging real-world and follow-up data on the safety and effectiveness of the mRNA vaccines in other jurisdictions is consistent with the effectiveness of the mRNA COVID-19 vaccines observed in the Phase 3 trial data. This further supports that scientific rigour was not compromised in the development of the mRNA COVID-19 vaccines.



How effective is the vaccine? How long does the protection last?

A:

Based on the respective Phase 3 trial data from Pfizer-BioNTech/Comirnaty. Moderna/Spikevax and Novavax/Nuvaxovid, the efficacy of the vaccines in preventing symptomatic COVID-19 disease from non-Delta/Omicron variants, after completion of the vaccine regimen, is around 90%. Locally, against the Delta variant, the mRNA vaccines 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.

While two doses of these vaccines provide excellent protection against severe disease, we have evidence that there is waning protection against infection over time, particularly with the Delta and Omicron variants. Locally, an increased risk of vaccine-breakthrough infections has been observed, starting from around six months after the completion of the first two vaccine doses. Booster vaccination is therefore needed to reduce COVID-19 infection and transmission.

Based on Phase 3 trial data from Sinovac, two doses of the Sinovac-CoronaVac vaccine demonstrated a vaccine efficacy of 51% against symptomatic infection with non-Delta/Omicron variants. There is no data on the protection against the Delta or Omicron variants. 

Antibody levels after the Sinovac-CoronaVac vaccination were low and declined rapidly within three to six months after completion the second dose returning to pre-vaccination levels by six months. Therefore, persons who are eligible to receive the Sinovac-CoronaVac vaccine are recommended to receive three doses of the vaccine as their primary vaccination series.

MOH will continue to monitor and review further data on the duration of immunity.


 Can vaccinated persons get infected with COVID-19? Are they less able to transmit the disease?

A:
The Pfizer-BioNTech/ Comirnaty and Moderna/Spikevax COVID-19 vaccines have been shown to reduce the risk of infection with the Delta variant by 40%. This means that vaccinated persons may still be vulnerable to infection.


There is also evidence that vaccinated individuals recover faster than unvaccinated persons. There is protection against onward transmission, even if it is not 100% protection. We continue to monitor the emerging data on the extent to which vaccination will reduce onward transmission of infection.

There is currently limited data on the protection conferred by the Sinovac-Coronavac and Novavax/Nuvaxovid vaccine against the Delta or Omicron variant.


[Updated 8 Jul] Who should not get the mRNA-based COVID-19 vaccines?

A:

The mRNA-based COVID-19 vaccines are not recommended for children under the age of 5 years for Pfizer-BioNTech/ Comirnaty COVID-19 vaccine and children under the age of 18 years for Moderna/Spikevax COVID-19 vaccine until more efficacy and safety data become available for these subgroups. 

Persons with a history of anaphylaxis to mRNA COVID-19 vaccine or its components SHOULD NOT receive the mRNA-based vaccine again. Anaphylaxis is a severe life-threatening reaction with two or more of the following three criteria:

a) Hives or face/eyelid/lip/throat swelling;
b) Difficulty breathing;
c) Dizziness.

Patients with the following high-risk allergic reactions to a previous dose of mRNA COVID-19 vaccine or its components SHOULD NOT be administered the vaccine.

a) Hives or face/eyelid/lip/throat swelling with onset within 4 hours post-vaccination
b) Painful swelling of the inner surfaces of the mouth and/ or large blisters spontaneously occurring at any time after vaccination.

Persons with a history of allergic reactions (including anaphylaxis) to other vaccines CAN receive the mRNA-based vaccine, unless they have a confirmed allergy specific to PEG (which is a component of the mRNA vaccine). Persons who were diagnosed with myocarditis after a dose of mRNA COVID-19 vaccines SHOULD NOT receive the vaccine again.

Persons who cannot get the mRNA vaccines due to the high-risk allergic reactions indicated above, including persons who a confirmed allergy specific to PEG, should be vaccinated with the Novavax/Nuvaxovid vaccine.

Persons who were diagnosed with myocarditis/pericarditis after a previous dose of mRNA COVID-19 vaccine SHOULD NOT receive the Novavax/Nuvaxovid vaccine.

The Sinovac-CoronaVac vaccine should only be considered for use by persons who cannot receive both the mRNA vaccines and Nuvaxovid.

  [Update 8 Jul] Who should not get the Novavax/Nuvaxovid COVID-19 vaccines?
 The Novavax/Nuvaxovid vaccine should not be received by children under the age of 18 years.

Persons with a history of anaphylaxis to the Novavax/Nuvaxovid vaccine or its components, or were diagnosed with myocarditis/pericarditis after a previous dose of an mRNA vaccine or Novavax/Nuvaxovid SHOULD NOT receive the Novavax/Nuvaxovid vaccine.

Anaphylaxis is a severe life-threatening reaction with two or more of the following three criteria:

a) Hives or face/eyelid/lip/throat swelling;
b) Difficulty breathing;
c) Dizziness.
 
 Who should not get the Sinovac-CoronaVac COVID-19 vaccines?
Persons who are able to take mRNA vaccines are encouraged to do so, in preference to the Sinovac-CoronaVac vaccine, given the higher efficacy of the mRNA vaccines.

The Sinovac-CoronaVac vaccine is not recommended for children under the age of 18 years until more efficacy and safety data is submitted to HSA for evaluation. 

Persons with a history of allergic reactions or  anaphylaxis to the Sinovac-CoronaVac vaccine, its components, or other inactivated vaccines SHOULD NOT receive Sinovac vaccine again. Anaphylaxis is a severe life-threatening reaction with two or more of the following three criteria:

a) Hives or face/eyelid/lip/throat swelling;
b) Difficulty breathing;
c) Dizziness.

 

Who are considered severely immunocompromised? Can severely immunocompromised persons receive the mRNA-based vaccine?

 A:

The following are some examples of severely immunocompromised persons, but there may be other examples not on this list.

·       Transplant within the past 3 months (solid organ or stem cell)
·       Aggressive immunotherapy (e.g. Rituximab) for non-cancer conditions

Severely immunocompromised persons can be vaccinated. However, they are encouraged to discuss their optimal timing for COVID-19 vaccination with their doctor, and would need to obtain a memo from their doctor to be vaccinated.

If in doubt, Individuals will also be assessed by the medical personnel at the vaccination sites for their suitability to receive the vaccination before they are vaccinated.

 Can individuals with a history of allergies or anaphylaxis to other medications, drugs, food, insect stings, or unknown triggers (idiopathic) take COVID-19 vaccine?
 Individuals with a history of anaphylaxis to other medications, drugs, food, insect stings, or unknown triggers (idiopathic) CAN be vaccinated.

There is no evidence to suggest that individuals with a history of anaphylaxis to non-vaccine related triggers are at higher risk of anaphylaxis to the COVID-19 vaccines.

However, individuals with an allergy to other inactivated vaccines should NOT receive the Sinovac-CoronaVac vaccine.


Can individuals with a history of NSAIDS-induced angioedema or multiple allergies be vaccinated with the mRNA-based vaccine?

 A:

Individuals with multiple allergies CAN be vaccinated, as long as the allergies are non-vaccine related.

 

Emerging local and international scientific evidence had shown individuals with NSAIDs-induced angioedema or even anaphylactoid reactions to NSAIDS CAN be vaccinated with a mRNA-based COVID-19 vaccine.


 

Can persons with active cancer be vaccinated?

A:

Cancer Patients Not on Treatment

Persons with active cancer who are NOT on treatment with chemotherapy, radiotherapy or immunotherapy CAN be vaccinated at any available vaccination site. Active cancer not on treatment is defined as:

  • Not being on any of the above treatment in the past 3 months AND
  • Not having planned treatment of the above in the next 2 months

Persons with a history of cancer, who are in remission, CAN be vaccinated at any available vaccination site.

 

Cancer Patients On Hormonal Treatment

Persons on active cancer hormonal therapy CAN be vaccinated at any available vaccination site.


Cancer Patients on Active Treatment
Persons on active cancer chemotherapy, radiation therapy or immunotherapy can be vaccinated if they have a memo from their treating oncologist/specialist.



Can pregnant or breastfeeding women receive the COVID-19 vaccine? 

A:
Pregnant or breastfeeding women can receive the COVID-19 vaccines.

Pfizer-BioNTech/Comirnaty and Moderna/Spikevax Vaccines
Internationally, a large number of pregnant and breastfeeding women have received a COVID-19 vaccination.  The Expert Committee on COVID-19 Vaccination (EC19V) has examined studies done to monitor women who were vaccinated when they were pregnant, and their babies. These studies were done on women at different trimesters of pregnancy and there is no evidence to suggest that the Pfizer-BioNTech/ Comirnaty or Moderna/Spikevax COVID-19 vaccine may cause harm to pregnant women or their babies.

Both Pfizer-BioNTech/ Comirnaty and Moderna/Spikevax COVID-19 vaccines are mRNA vaccines. As mRNA vaccines are not live vaccines, they are biologically unlikely to adversely affect breastfed babies. In addition, the breast milk of vaccinated mothers may help to protect their babies from COVID-19 due to antibodies in breast milk. There have also been no vaccine-related side effects reported in the babies who were breastfed by mothers who received the vaccine while breastfeeding.

Sinovac-CoronaVac and Novavax/Nuvaxovid Vaccine
There is currently limited data in pregnant women. Nevertheless, The Sinovac-CoronaVac vaccines is an inactivated vaccine, while Novavax/Nuvaxovid is a protein subunit vaccine. These vaccines are routinely used in many other vaccines with a documented good safety profile, including in pregnant women.

Will the COVID-19 vaccine cause infertility?

 A:

There is currently no evidence that the COVID-19 vaccines can cause infertility in vaccine recipients.


 

Is COVID-19 vaccination safe for those with chronic illness such as hypertension, high cholesterol and diabetes?

A:

Persons with chronic illnesses are recommended to receive the vaccine for personal protection as well as protecting their loved ones. The participants of Pfizer-BioNTech/ Comirnaty’s and Moderna's phase 3 trials and other studies included persons with medical comorbidities, who were at risk of serious, life-threatening disease and death from COVID-19 infection, and demonstrated effectiveness with no safety concerns reported in this group. Studies on the Novavax/Nuvaxovid and Sinovac-CoronaVac vaccines have also included persons with chronic diseases without safety concerns reported.

 

Can I receive another (non-COVID-19) vaccine at the same time as COVID-19 vaccine? How long do I have to wait before getting other vaccines? 

A:There is no data on administering COVID-19 vaccine at the same time as other non-COVID-19 vaccines. A minimum interval of 14 days is encouraged before or after any other vaccines, but is not strictly necessary 
 

Can I donate blood after receiving the COVID-19 vaccine?

A:

The Health Sciences Authority (HSA) and the blood bank has implemented a new blood donation eligibility guideline for donors who received a COVID-19 vaccine.  

The deferral period may vary depending on the type of vaccine received or if you developed symptoms after receiving the vaccine.  Please click here  for more information.


 [Updated 8 Jul] What is myocarditis and pericarditis? Can the vaccine lead to myocarditis and pericarditis?
 A:Myocarditis and pericarditis are inflammatory conditions affecting the heart muscles and the outer lining of the heart, respectively. Patients may present with symptoms such as chest pain, shortness of breath or abnormal heartbeats. Local incidence rates remain low and the cases are usually mild and recover well.
 
As a precaution, all vaccinated persons, in particular adolescents and younger persons, who have received any dose of the vaccine, should avoid exercise or strenuous physical activity such as running, weightlifting, competitive sports, or playing ball games for two weeks after a dose of the mRNA-based COVID-19 vaccines or the Novavax/Nuvaxovid vaccine.

 

[Updated 8 Jul] What is the recommendation for persons who are unable to receive the mRNA vaccines (i.e. Pfizer-BioNTech/Comirnaty or Moderna/Spikevax vaccines)? 

 A:

Persons who are unable to receive the mRNA vaccines are recommended to receive the Novavax/Nuvaxovid vaccine, except those who were diagnosed with myocarditis/pericarditis after a previous dose of an mRNA vaccine. The Sinovac-CoronaVac vaccine should only be considered for use in persons who are medically ineligible to receive mRNA vaccines and the Novavax/Nuvaxovid vaccine. 

Under the National Vaccination Programme, persons who are unable to receive the mRNA and Novavax/Nuvaxovid vaccines are recommended to complete their primary vaccination course with the Sinovac-CoronaVac vaccine:
a.  Persons who had not received any COVID-19 vaccines are recommended to receive 3 doses of the Sinovac-CoronaVac vaccine;
b.  Persons who had received the first dose of the mRNA or Novavax/Nuvaxovid vaccine are recommended to receive 2 doses of the Sinovac-CoronaVac vaccine.

 

I am unsure if it is medically safe for me to be vaccinated. What should I do?

A:

MOH has put in place steps to ensure it is medically safe before you are vaccinated. Before making appointments for vaccination, you will be prompted to complete an online screening form, which contains medical questions to screen out those who are unsuitable for the current COVID-19 vaccines (i.e. Pfizer-BioNTech/ Comirnaty, Moderna/Spikevax , Novavax/Nuvaxovid and Sinovac-CoronaVac). Once you have cleared the online screening, you will be invited to book your appointments for vaccination. In the event that you have booked your appointments but remain unsure if you should receive the vaccine, there will be another round of medical screening conducted at your preferred vaccination site on the day of vaccination. You may seek clarifications or further assessment with the medical professionals onsite to assist with any medical queries that you may have. If you are unsure of your allergy history, the vaccination sites are able to securely access your allergy history if required.

Alternatively, you may consult your regular doctor for advice if you should receive the COVID-19 vaccination. Please note that any charges incurred for such pre-vaccination consultation with your doctor are not covered under the COVID-19 vaccination programme. Your doctor may provide a memo on your condition which will be useful for the medical team at the vaccination site to assess your suitability for vaccination. However, the final decision as to whether you should proceed with vaccination will be made by the medical professionals at the vaccination site.



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