A vaccine to prevent COVID-19 is perhaps the best hope for ending the pandemic. Currently, there is no vaccine to prevent infection with the COVID-19 virus, but researchers are racing to create one.
Coronavirus vaccine research
Coronaviruses are a family of viruses that cause illnesses such as the common cold, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). COVID-19 is caused by a virus that's closely related to the one that causes SARS. For this reason, scientists named the new virus SARS-CoV-2.
While vaccine development can take years, researchers aren't starting from scratch to develop a COVID-19 vaccine. Past research on SARS and MERS vaccines has identified potential approaches.
Coronaviruses have a spike-like structure on their surface called an S protein. (The spikes create the corona-like, or crown-like, appearance that gives the viruses their name.) The S protein attaches to the surface of human cells. A vaccine that targets this protein would prevent it from binding to human cells and stop the virus from reproducing.
Coronavirus vaccine challenges
Past research on vaccines for coronaviruses has also identified some challenges to developing a COVID-19 vaccine, including:
Ensuring vaccine safety. Several vaccines for SARS have been tested in animals. Most of the vaccines improved the animals' survival but didn't prevent infection. Some vaccines also caused complications, such as lung damage. A COVID-19 vaccine will need to be thoroughly tested to make sure it's safe for humans.
Providing long-term protection. After infection with coronaviruses, re-infection with the same virus -- though usually mild and only happening in a fraction of people -- is possible after a period of months or years. An effective COVID-19 vaccine will need to provide people with long-term infection protection.
Protecting older people. People older than age 50 are at higher risk of severe COVID-19. But older people usually don't respond to vaccines as well as younger people. An ideal COVID-19 vaccine would work well for this age group.