Key quotes: Understanding how COVID-19 vaccines work

COVID-19 vaccines
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by Lydia Antonio-Vila, International Journalists’ Network

A year after COVID-19 was declared a national emergency, vaccines have finally arrived, with the U.S. averaging 2 million vaccine doses administered per day. But the arrival of vaccines also brings an explosion of information — some of it untrue. Dr. Galit Alter, a professor of medicine and a group leader at the Ragon Institute of MGH, MIT and Harvard, spoke with Patrick Butler, ICFJ’s Vice President of Content and Community, about vaccines.

How does the virus affect our system?

A pink circle surrounds green lines labeled "mRNA" and is covered in red spikes labeled "Spikes"
A cartoon of a viral particle from a presentation by Dr. Alter

“While some vaccine developers decided to use the entire virus as a potential platform to drive immunity, most vaccine developers actually ended up focusing on a specific part of the virus, which is the Spike of the virus,” said Dr. Alter.

Dr. Alter explained that the virus causes COVID-19 disease through its ability to use the Spike protein to interact with a protein on the surface of our lung cells, called the ACE-2 receptor.

“Once that spike protein interacts with the ACE-2, this gives permission to the virus to now enter the cells where it can replicate, multiply and begin to spread and cause disease,” said Dr. Alter.This is the interaction that vaccine developers seek to block.

“What’s interesting about this particular ACE-2 receptor is that they are not only present on the surface of lung cells. They are also found in the gut, our blood vessel walls, heart cell wall and in some cells that live in our respiratory passageways, which allow us to smell and taste things,” she explains. This is why there are reports of people not being able to taste or smell when infected with the virus.

How do vaccines work?

In an illustration, a group of people splits into three separate groups: No vaccine, BLOCK disease, BLOCK transmission & disease. Number of severe infections falls in group 2, but group 3 has no infections at all.

“Some vaccines will work by completely blocking infection,” explained Dr. Alter. This method is the most effective, as shown by the group on the right in the diagram above.

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