Medically Reviewed by Dr Ho Ying Jie (M.B.B.S. Singapore & Family Physician of Singapore Medical Council)
The COVID-19 pandemic has had a profound impact on global health, prompting the rapid development and distribution of multiple vaccines. These vaccines have played a crucial role in controlling the spread of the virus, reducing severe cases, and ultimately saving lives.
However, with several different vaccines available, it can be confusing for many to understand the key differences between them.
This article will provide a detailed comparison of the available COVID-19 vaccines, focusing on the vaccines used in Singapore, and discuss their effectiveness, side effects, and overall benefits. It will also highlight the importance of COVID vaccination in managing the pandemic.
Overview of the Available COVID-19 Vaccines in Singapore
In Singapore, multiple COVID-19 vaccines have been approved for emergency use and are available to the public through various health channels, including government vaccination programs. As of now, the vaccines that have been widely used in Singapore include:
- Pfizer-BioNTech (Comirnaty)
- Moderna (Spikevax)
- Sinovac (CoronaVac)
- Johnson & Johnson (Janssen)
Each vaccine has its unique characteristics, but they all share the common goal of providing immunity against the SARS-CoV-2 virus, which causes COVID-19.
1. Pfizer-BioNTech (Comirnaty)
The Pfizer-BioNTech vaccine, also known as Comirnaty, is an mRNA vaccine, one of the most advanced types of vaccines used for COVID-19. It was the first vaccine to receive approval for emergency use in Singapore.
How It Works
The Pfizer-BioNTech vaccine uses messenger RNA (mRNA) to instruct cells to produce the spike protein found on the surface of the SARS-CoV-2 virus. This stimulates an immune response, including the production of antibodies, which help to protect the body if it encounters the virus in the future.
Efficacy and Protection
Comirnaty has been shown to have an efficacy rate of approximately 95% in preventing symptomatic COVID-19 infection, which makes it one of the most effective vaccines available. It also provides strong protection against severe disease, hospitalization, and death due to COVID-19.
Side Effects
Common side effects of the Pfizer-BioNTech vaccine include pain at the injection site, fever, fatigue, and headaches. These side effects are typically mild and subside within a few days. More serious side effects, such as an allergic reaction, are rare.
2. Moderna (Spikevax)
The Moderna vaccine, also an mRNA-based vaccine, works similarly to Pfizer-BioNTech by using mRNA to stimulate an immune response against the SARS-CoV-2 virus.
How It Works
Like the Pfizer-BioNTech vaccine, the Moderna vaccine uses lipid nanoparticles to deliver mRNA into the body. The mRNA prompts cells to produce the spike protein, which in turn triggers an immune response. The Moderna vaccine requires two doses, administered 28 days apart.
Efficacy and Protection
Moderna’s vaccine has demonstrated an efficacy of about 94.1% in preventing symptomatic COVID-19 infection. It is similarly effective in reducing the risk of severe illness, hospitalization, and death.
Side Effects
The side effects of the Moderna vaccine are similar to those of the Pfizer-BioNTech vaccine and may include pain at the injection site, fatigue, muscle aches, fever, and headaches. Most side effects are mild and resolve on their own within a few days. In rare cases, some individuals may experience more severe reactions like myocarditis or blood clotting, although these are extremely rare.
3. Sinovac (CoronaVac)
The Sinovac vaccine, also known as CoronaVac, is an inactivated virus vaccine, which works differently from the mRNA vaccines. It is based on a traditional vaccine technology where the virus is killed and then introduced into the body to stimulate an immune response.
How It Works
CoronaVac contains an inactivated form of the SARS-CoV-2 virus. When injected, the immune system recognizes the virus as foreign and produces an immune response, including antibodies. These antibodies can protect the body from future infections.
Efficacy and Protection
The Sinovac vaccine has shown varying efficacy rates in different trials, with reported protection against symptomatic COVID-19 ranging from 50% to 83%. While the efficacy is lower than the mRNA vaccines, it still provides significant protection against severe illness, hospitalization, and death.
Side Effects
Side effects from the Sinovac vaccine are generally mild, with common reactions including pain at the injection site, fatigue, and low-grade fever. There are no known severe side effects related to the vaccine, and it has been deemed safe for most people.
4. Johnson & Johnson (Janssen)
The Johnson & Johnson vaccine, also known as Janssen, is a viral vector vaccine. It uses a harmless adenovirus (a different virus from SARS-CoV-2) to deliver the genetic material needed to produce the spike protein of the SARS-CoV-2 virus.
How It Works
The viral vector vaccine delivers the genetic material into human cells, prompting them to produce the spike protein. This then triggers an immune response, providing protection against COVID-19. A notable advantage of the Janssen vaccine is that it requires only a single dose, unlike the other vaccines which require two doses.
Efficacy and Protection
Janssen’s vaccine has an efficacy of about 66% in preventing moderate to severe COVID-19 infection, and it is also highly effective in preventing severe disease, hospitalization, and death.
Side Effects
The side effects of the Johnson & Johnson vaccine are similar to those of the mRNA vaccines, including pain at the injection site, fever, headache, and fatigue. However, rare side effects such as blood clots have been observed, although these events are extremely uncommon.
Key Differences Between the COVID-19 Vaccines
Vaccine Type
- mRNA Vaccines (Pfizer-BioNTech, Moderna): These vaccines use messenger RNA to instruct cells to produce the spike protein and trigger an immune response.
- Inactivated Virus Vaccine (Sinovac): This vaccine uses a killed version of the virus to stimulate an immune response.
- Viral Vector Vaccine (Johnson & Johnson): This uses a harmless adenovirus to deliver the spike protein’s genetic material.
Number of Doses
- Pfizer-BioNTech, Moderna: Two doses required.
- Johnson & Johnson: One dose required.
- Sinovac: Two doses required.
Efficacy
- Pfizer-BioNTech and Moderna: Both have high efficacy rates of around 94-95% in preventing symptomatic COVID-19.
- Sinovac: Has an efficacy rate of 50-83%, but still provides good protection against severe disease.
- Johnson & Johnson: Efficacy is approximately 66%, but it is effective in preventing severe illness and death.
Side Effects
- All vaccines generally have mild side effects such as pain at the injection site, fatigue, and fever. More serious reactions, like allergic reactions or myocarditis, are rare but have been reported in some cases.
Why COVID Vaccination is Crucial
Getting vaccinated is a vital step in protecting yourself and others from COVID-19. Vaccines reduce the likelihood of severe illness, hospitalization, and death, while also contributing to herd immunity, which helps protect those who cannot be vaccinated, such as individuals with compromised immune systems. In Singapore, the government has made it easy for everyone to access vaccines, and the benefits far outweigh the risks.
Get Vaccinated Today: Schedule Your COVID Vaccination Appointment at Keystone Clinic & Surgery!
Understanding the differences between the available vaccines can help you make an informed decision about your health. Whether it’s the highly effective mRNA vaccines (Pfizer-BioNTech and Moderna), the traditional inactivated virus vaccine (Sinovac), or the single-dose viral vector vaccine (Johnson & Johnson), all of these options have been shown to provide strong protection against the virus.
Choosing to get vaccinated is one of the most important steps you can take in the fight against COVID-19. By protecting yourself, you’re also helping to protect your community. Visit Keystone Clinic & Surgery to book your COVID vaccination and help keep yourself and others safe.
References
Yalemedicine.org. 2024. Comparing the COVID-19 Vaccines: How Are They Different?. https://www.yalemedicine.org/news/covid-19-vaccine-comparison
Mayoclinic.org. Different Types of COVID-19 Vaccines. How They Work. https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/different-types-of-covid-19-vaccines/art-20506465
Webmd.com. 2022. COVID Vaccines Compared. https://www.webmd.com/vaccines/covid-19-vaccine/covid-vaccines-compared