You may feel we’ve been living with COVID-19 forever. But there’s still much we don’t know about the virus.

As we show in GPG’s latest Back to Work analysis, the three big unknowns for the disease are warm weather, herd immunity and superspreaders.

It is a hopeful possibility warm weather will slow the spread of COVID-19, as is the case with seasonal flu. A working paper published by Harvard suggests some slowing of the spread in warmer climes but not to a meaningful level of reduction.

The second open question is whether the U.S has achieved herd immunity. With limited early testing and tracing, it’s not clear how many Americans have been infected with the virus and recovered, providing potential immunity. 

Early studies suggest even in New York City, only 20% of residents have been infected, far from the threshold required to give effective antibody protection for the population. 

Complicating the matter further, the World Health Organization has warned there is currently no evidence to suggest antibodies provide immunity from a second infection.

Finally, virus superspreaders – individuals who seem to pass the virus onto a larger number of people than others who are infected–remain a mystery. Studies show 10% of cases have caused 80% of new infections. 

Why this is the case remains an open question for researchers.

Read more in the full Back to Work memo here.