7 Months On– What we know and what we don’t know about COVID-19: STAT

Here’s a new article from STAT on August 17 that summarizes what we know about the virus that causes COVID-19– and what we still don’t know that continues to be a “pressing question.”

Things we still don’t know: first, how long does recovery from the virus protect us against re-infection? Prior experience with the coronaviruses that cause “common colds” tells us that protection may last less than a year. There are four known coronaviruses that cause colds, and these viruses circulate through the human population on a regular basis. It is possible to catch a cold once a year, at least– we know this from personal experience.

Second, what happens when you get a re-infection with SARS-COV-2? Again, experience tells us that repeat infection with cold viruses leads to less severe symptoms the second, third, and subsequent times. We don’t know if this is true with the novel coronavirus.

Third, how much (or how many) virus does it take to catch an infection? We know that some viruses are very efficient, for example measles. But we don’t know with this virus what the infectious dose is.

Fourth, we don’t know how many people have been infected and not counted. Current information suggests that roughly ten times more people have been infected than the confirmed case count tells us. That’s just a guess. Lack of sufficient tests has led to inadequate counts, in some places worse than others.

In the US, a drop in the number of tests performed, particularly in hard-hit Republican-led states, has led to an appearance of improvement in daily case counts– but this is quite possibly misleading. The rate of positive cases in proportion to those tested is going up, suggesting that we’re not testing enough people.

Finally, we still don’t know why some people get sick and others don’t. We have some evidence that genetic factors protect some people and make others more susceptible. We still don’t have the full picture. We’re still not sure why children don’t appear to get as sick, even though they produce equal or greater amounts of virus.

Read the article for more information about what we have learned and what we haven’t. It’s a good summary of current thinking.