What Is the Coronavirus?
Plus: How can I avoid catching it? Is Covid-19 more deadly than the flu? Our in-house Know-It-Alls answer your questions.
In the US and other developed countries, particularly in the global north, mystery illnesses don’t strike that often. People are used to having answers and a plan for avoiding getting sick. In these places, vaccines have already eliminated infectious diseases that were once common, including polio , hepatitis , and the measles . If you get your flu shot every year, the worst thing you’ll usually pick up is a case of the common cold.
Which is perhaps why Americans can’t seem to wait to get their hands on a Covid-19 vaccine. President Donald Trump told pharmaceutical executives and public health officials in a White House meeting on Monday that he wants one ready before the election in November.
For the record, that would be impossible. Developing vaccines that are safe and effective takes time, investment, and good science. Developing a vaccine for a coronavirus like the one that causes Covid-19 comes with even more challenges. But at least 30 companies and academic institutions are trying. Here’s your guide to everything you need to know about those efforts. Check back often—we’ll be keeping it updated with any notable progress or setbacks.
What’s In a Vaccine?
Vaccines all work on the same basic principle: Scientists try to make something that closely resembles a pathogen, and then expose a person’s immune system to it through a small dose administered as an injection. Ideally, the immune system develops a strong memory of the pathogen, so that the next time the person is exposed, their body will mount an attack before the infection can take hold. The trick is to do this without making the person seriously ill from the vaccine itself. There are a few different methods for making vaccines, but they all must strike this delicate balance.
One way to make a vaccine is to weaken, or attenuate, the microorganism while still keeping it alive. The most common method for doing this is growing several generations of the pathogen in environments other than human cells, so that it evolves away from causing disease in humans. By repeatedly culturing live viruses or bacteria in animal cells, scientists can essentially create a bunch of mutants. Then it’s a matter of selecting the mutant strains that can replicate in human cells but don’t cause disease like their wild ancestor. The trick is that these imposters still have to look enough like the original virus to accurately train the immune system to fend it off. Examples of attenuated vaccines include those for measles, mumps, and tuberculosis.
Another type is called an inactivated vaccine, which is made from a dead version of the whole virus or bacteria after it’s been killed with heat or chemicals. This type of vaccine can also be made using smaller pieces of the microbe , which by themselves are not considered alive.