30 September 2023

Explainer: Facts about COVID-19 vaccines

There have been confusion and misleading claims about the development of COVID-19 vaccines since the beginning of the pandemic.

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Pregnant woman receiving an influenza vaccination at the Maternal and Child Hospital in Vientiane, Laos. (Source: The U.S. Centers for Disease Control and Prevention)

[This article was published in August 2020. An update is underway.]

What are vaccines? What is vaccination?

Vaccination is a method of protecting people from diseases before they actually come into contact with them.

How does a vaccine work?

A vaccine achieves immunity from diseases by training the body’s immune system to produce antibodies to fight against the pathogens that cause infectious diseases.

How are vaccines developed and tested before use? How long does it usually take to develop a new vaccine?

There are multiple stages of vaccine development, each with different objectives. Not all vaccine candidates make it past all stages of development. The failure rate is high and many vaccine candidates never make it to clinical trials in humans.

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(Source: US National Library of Medicine National Institutes of Health & Oxfam International)
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A microbiologist uses an electronic pipetter to extract reconstructed 1918 Pandemic Influenza virus. (Source: The U.S. Centers for Disease Control and Prevention, via Unsplash)
How much does it cost to bring a vaccine from development to market?

Researching and developing a vaccine can be very expensive. Estimates vary, but one academic paper suggests that it costs between US$200 to $500 million to bring a vaccine from the concept stage to market.

How will a vaccine help stop the spread of COVID-19?

A vaccine would help stop the spread of COVID-19 by stimulating the immune system to produce corresponding antibodies to fight it.

What is herd immunity?

If the proportion of people who are immune to infection becomes large enough, it would lead to a decline in the rates of infection.

How many vaccines are in development? What is the progress of vaccine development right now?

Scientists are developing more than 100 coronavirus vaccines using a range of techniques, including some that are well-established and others that have never been approved for medical use before.

What are the different approaches to vaccine development?

Scientists are taking many different approaches to developing SARS-CoV-2 vaccines. There are at least four different vaccine technologies being explored to develop a vaccine for COVID-19.

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(Source: The New York Times & The New England Journal of Medicine)
Are the vaccines effective for all kinds of people?

Researchers say vaccines may be less effective for people who are obese. Some people also have health conditions that make them poor candidates for vaccination.

What are some misleading claims surrounding vaccine development?
  • Bill Gates is not trying to implant trackers through vaccines.
    This common conspiracy has been debunked by many journalists around the world.
  • The vaccine trial volunteer in the U.K. is alive.
    Another popular debunked story claimed a participant in a vaccine trial in the U.K. died after receiving a shot. This was later proven to be false. Microbiologist Elisa Granato, the participant said to be dead, appeared in a video interview with the BBC on April 26, 2020.
  • Vaccination will not lead to infection.
    Another common claim is that any future COVID-19 vaccine will cause the vaccinated person to become infected with the virus. Although vaccines do contain some portion or versions of viruses, the virus is altered and designed in such a way that they will not cause disease or infection.