What we know about COVID-19 seems to change by the minute.

Its understandable, given the massive scale of the global pandemic. Right now, there are more than 63 million known cases around the world and counting. The virus is also relatively new to the medical world, so researchers are learning as they go.

The amount of information out there is dizzying. Its hard to keep track of whats known, whats a myth and what guidance we should follow. Thats why weve rounded up five of the most important new things we learned about COVID-19 in November:

1. Vaccines could arrive by the end of 2020.

November was a remarkable month in the race to develop a COVID-19 vaccine. Drug maker Pfizer announced that the vaccine it is developing is more than 90% effective, and it now seems possible that around 6 million doses could be available in the United States by mid-December.

Moderna announced similarly encouraging results, releasing data that suggests its vaccine is 94% effective. The company asked regulatory bodies in the U.S. and Europe including the FDA to allow emergency use of its vaccine . That means some Americans could receive the vaccine as soon as Dec. 21.

Those breakthroughs were exciting for several reasons, one of which is that, from a scientific standpoint, both vaccines are just kind of ... remarkable. They rely on a pretty new type of technology called messenger RNA or mRNA vaccines.

As the Centers for Disease Control and Prevention explains : To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Not mRNA vaccines. Instead, they teach our cells how to make a protein or even just a piece of a protein that triggers an immune response inside our bodies. In turn, that immune response produces antibodies that protect against COVID-19 infection.

Of course, vaccine distribution is going to be extremely challenging, particularly because mRNA vaccines need to be handled and stored in a very specific way. (The Pfizer vaccine, for example, must be kept at -94 degrees Fahrenheit. ) There are questions about production capacity, about how states plan to distribute the vaccine (or vaccines, as these will require two doses) and who is considered highest priority. Experts are predicting that the earliest a vaccine will be widely available to most Americans is in April and likely later for kids .

2. Restaurants and gyms may be the biggest drivers of COVID-19 infection.

As we anxiously await a vaccine, COVID-19 cases around the U.S. continue to soar. A new model, published in the journal Nature last month , pointed to what may well be the biggest culprits: cafes, restaurants and gyms.

The model relied on mobile phone data from 10 major U.S. cities, and the researchers say they were able to faithfully estimate the contact network between 100 million people for every hour of the day.

Their model corroborated what has been suggested in several other studies: Indoor venues, like restaurants and gyms, are major drivers of infection and may be significantly contributing to outbreaks in various areas.

Thats important data to have in mind as we navigate this winter, both at a policy level (as regulators decide what to close, what to cap and when) and at a personal level (as all of us decide what activities to partake in indoors).

However, the experts also caution against reading too much into the findings as the model relied on data from last spring, when our collective mask-wearing habits were very different. For example, eating in a restaurant now may be less risky than it was in March and April now that mask mandates are widely in place.

There are also other areas, like long-term care facilities and prisons, that are a leading source of spread, according to a November report from The New York Times . Finally, current evidence suggests that small gatherings among friends and family may also drive COVID-19 infections . So the Nature studys findings are not a definitive list of where COVID-19 mainly spreads.