Understand the COVID-19 vaccines available globally

It's important that we all understand how the various COVID-19 vaccines being developed globally work. This article looks at various global front-runner vaccines in detail. We summarise what you need to know, from how the vaccine works to efficacy, storage, side-effects, dose and more.

- Want to better understand various words and terms used in reference to vaccines? Just refer to our vaccine vocabulary article.

Find out all you need to know about South Africa's vaccine rollout plan and process.

Now, let's take a look at each of the various global front-runner vaccines in detail.

Johnson & Johnson vaccine (USA)

• How it works/technology used to create this vaccine: DNA/Viral Vector
• Efficacy: 64% efficacy against moderate to severe disease
  • 82% against severe disease against South African 501Y.V2 variant.
• Storage: For 3 months when refrigerated at 2 to 8 deg C. And, for 2 years when frozen at -20 deg C.
• Side-effects: Initial safety information released for the vaccine shows that the most common reactions after the vaccine was administered included injection site pain, fatigue, headache and muscle aches. Learn more here.
• Age groups that the vaccine has been authorized for: ages 18 and up
• Number of vaccine doses needed: One dose (Important in the African context as people do not need to return for a second dose of the vaccine. This is particularly relevant to people in under-resourced, far-flung or rural areas)

Pfizer-BioNTech vaccine (USA/Germany)

• How it works/technology used to create this vaccine: mRNA
• Efficacy: 95% after the second dose.
  • (Efficacy against variants unknown at time of writing, however testing was underway)
• Storage: 5 days under normal refrigeration (2 to 8 deg C). Beyond 5 days, this vaccine must be stored at - 70 deg C
• Side-effects: Side effects (such as fever, chills, tiredness, and headache) throughout the body were more common after the second dose of the vaccine. Most side effects were mild to moderate. Allergic reaction could occur within 4 hours of getting vaccinated, including symptoms such as hives, swelling, or wheezing (respiratory distress). This includes allergic reactions to polyethylene glycol (PEG) and polysorbate. Learn more here.
• Age groups that the vaccine has been authorized for: ages 18 and up
• Number of vaccine doses needed: 2 doses, 21 days apart

Moderna vaccine (USA)

• How it works/technology used to create this vaccine: mRNA
• Efficacy: 94.5%
  • (Efficacy against variants unknown at time of writing, however testing was underway)
• Storage: for 30 days under normal refrigeration (2 to 8 deg C), and for 6 months at - 20 deg C (freezer)
• Side-effects: Side effects (such as fever, chills, tiredness, and headache) throughout the body were more common after the second dose of the vaccine. Most side effects were mild to moderate. Allergic reaction could occur within 4 hours of getting vaccinated, including symptoms such as hives, swelling, or wheezing (respiratory distress). This includes allergic reactions to polyethylene glycol (PEG) and polysorbate. Learn more here.
• Age groups that the vaccine has been authorized for: ages 18 and up
• Number of vaccine doses needed: 2 doses, 28 days apart.

Oxford/AstraZeneca vaccine (UK/USA)

• How it works/technology used to create this vaccine: DNA/Viral Vector
• Efficacy: 70% against the COVID-19 virus variant dominant in the first global wave of COVID-19 infections. (in clinical trials, when the vaccine was given as a half dose followed by a full dose a month later, efficacy was reported at 90%. When two full doses were given, a month later, efficacy was reported at 62%).
  • On 7 February 2021, preliminary data showed that this vaccine offers minimal protection (only a 22% efficacy) against illness caused by South Africa's now dominant 501Y.V2 COVID-19 virus variant (responsible for roughly 90% of COVID-19 infections in the country's second wave of infection)
• Storage: Refrigerate at a temperature of between 2 and 8 deg C (temperatures attainable in most common fridges) for up to 6 months.
• Side-effects: Mild to moderate in severity and usually resolve within a few days of vaccination: injection site tenderness or pain, headache, fatigue; muscle pain, feeling unwell; fever, chills, joint pain and/ or nausea.
• Age groups that the vaccine has been authorized for: ages 18 and up
• Number of vaccine doses needed: 2 doses, 4 -12 weeks apart

Novavax vaccine (UK)

• How it works/technology used to create this vaccine: A protein-based vaccine / protein adjuvant vaccine / protein subunit vaccine. This vaccine uses a custom-made form of the spike protein which is found on the outside of the virus that causes COVID-19 disease. In essence, this engineered protein mimics the spike protein found on the real COVID-19 virus. This spike protein particle is combined with a plant-based ingredient that generates an enhanced immune response. The spike protein is incorporated as a nanoparticle that is injected into the body to stimulate the immune system to produce antibodies against the real COVID-19 virus. This vaccine also induces a T-Cell response (another type of immune system cell that also helps us to overcome illness, and confers a degree of immunity going forward).
• Efficacy: 89.3% in the case of infection with the strain of COVID-19 dominant in 2020.
  • 85% effective against the COVID-19 variant identified in the United Kingdom
  • 60% effective against the variant identified in South Africa. Novavax is working on a new vaccine that will target the new variant and expects to start testing it in a few months.
• Storage: Refrigerate at a temperature of between 2 and 8 deg C (temperatures attainable in most common fridges)
• Side-effects: pain at the injection site, headaches, muscle pain and fatigue. Learn more here.
• Age groups that the vaccine has been authorized for: ages 18 and up
• Number of vaccine doses needed: 2 doses, 3 weeks apart

(Gamelya) Sputnik V vaccine (Russia)

• How it works/technology used to create this vaccine: DNA/Viral Vector
• Efficacy: 91.4%
  • (Efficacy against variants unknown at time of writing, with research underway)
• Storage: Refrigerate at a temperature of between 2 and 8 deg C (temperatures attainable in most common fridges)
• Side-effects: Flu-like symptoms which may include fever, fatigue, weakness and headaches
• Age groups that the vaccine has been authorized for: ages 18 and up
• Number of vaccine doses needed: 2 doses, 2 weeks apart

Sinovac (CoronaVac) vaccine (China)

• How it works/technology used to create this vaccine: Inactivated virus: This vaccine uses virus particles that have been killed so they cannot make us sick. However the process keeps the spike proteins on the outside of the virus in place and this means that when we are vaccinated we expose the body's immune system to the actual shape of the virus in a safe way. Then, the immune system can be trained to respond to the real, live virus should it ever be encountered in future.
• Efficacy: Vaccine efficacies of 50%, 65%, 78% and 91% from various trial results from participating countries have been reported.
  • (Efficacy against variants unknown at time of writing)
• Storage: Refrigerate at a temperature of between 2 and 8 deg C (temperatures attainable in most common fridges) for five months
• Side-effects: Fatigue and fever and low-grade muscle pain
• Age groups that the vaccine has been authorized for: Ages 65 and over
• Number of vaccine doses needed: 2 doses 3 to 4 weeks apart

Sinopharm vaccine (China)

• How it works/technology used to create this vaccine: Inactivated virus: This vaccine uses virus particles that have been killed so they cannot make us sick. However the process keeps the spike proteins on the outside of the virus in place and this means that when we are vaccinated we expose the body's immune system to the actual shape of the virus in a safe way. Then, the immune system can be trained to respond to the real, live virus should it ever be encountered in future.
• Efficacy: 79.34%
  • (Efficacy against variants unknown at time of writing)
• Storage: Refrigerate at a temperature of between 2 and 8 deg C (temperatures attainable in most common fridges) for 24 months
• Side-effects: Headaches, muscle aches and fever
• Age groups that the vaccine has been authorized for: Aged 18 to 59
• Number of vaccine doses needed: 2 doses 3 to 4 weeks apart

CanSino Biologics vaccine (China)

• How it works/technology used to create this vaccine: It uses a modified common cold virus known as adenovirus type-5 (Ad5) to carry genetic material from the coronavirus protein into the body.
• Efficacy: Interim analysis of data showed 65.7% effective in preventing symptomatic cases and 95.47%% effective in preventing severe disease 14 days after vaccination. This fell to an efficacy rate of 65.28% at preventing symptomatic cases and 90.07% at preventing severe disease 28 days after a single dose. Late-stage clinical trials with the vaccine are still ongoing, and ultimate efficacy is not yet known. The vaccine has gained emergency use authorisation in Pakistan and Mexico and in China, been administered to military personnel since June 2020. However no detailed study results are publicly available yet.
  • (Efficacy against variants unknown at time of writing)
• Storage: Refrigerate at a temperature of between 2 and 8 deg C (temperatures attainable in most common fridges) for 24 months
• Side-effects: Headaches, muscle aches and fever
• Age groups that the vaccine has been authorized for: Late-stage clinical trials with the vaccine are ongoing.
• Number of vaccine doses needed: One

You can learn more about vaccine safety and side effects here.