No one was prepared for the coronavirus pandemic.
But after a long 2020, here are 13 things about the virus that we didn't know at the start of the year.
https://www.buzzfeednews.com/article/zahrahirji/13-coronavirus-facts-2020?bftwnews&utm_term=4ldqpgc#4ldqpgc
But after a long 2020, here are 13 things about the virus that we didn't know at the start of the year.

1) The virus was circulating in China as early as November and in the rest of the world by January, long before countries closed their borders. Scientists are still learning about how it came to infect humans, which can help prevent the next pandemic. https://www.buzzfeednews.com/article/danvergano/more-coronavirus-pandemics-warning
2) COVID-19 can look very different from person-to-person. The CDC has outlined 11 main symptoms to watch for, including fever, cough, shortness of breath, and loss of taste or smell. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html
3) People can be infectious even if they don’t have symptoms. The current evidence suggests that someone can spread the virus before developing symptoms — or without developing them at all.
4) Masks work, whether they're cloth or medical-grade. The more people wear masks, the less the virus spreads. And there’s some emerging evidence that masks also offer protection to healthy people that wear them. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31142-9/fulltext#%20
5) The virus can spread in the air — and do it beyond the six feet commonly cited in social distancing guidelines. The CDC didn't acknowledge this until October. https://www.buzzfeednews.com/article/azeenghorayshi/cdc-airborne-update-masks-ventilation
6) A small percentage of people are "superspreaders" and responsible for most infections. For example, dozens of people got infected and sick at large indoor weddings in Ohio and Maine. https://www.buzzfeednews.com/article/clarissajanlim/coronavirus-outbreak-wedding-maine-one-dead
7) We don’t need ventilators as much as we thought. They're still considered crucial, but better understanding of how COVID-19 kills many patients has lessened the crush for the machines.
8) We now know illnesses that come with age, including diabetes and cancer, increase the danger of the coronavirus — not just old age itself. The CDC has recommended those over 75 get shots ahead of others because of their high rates of these conditions. https://www.buzzfeednews.com/article/skbaer/covid-vaccine-frontline-workers-older-adults-cdc
9) CDC’s early guidance suggested that pregnant people and fetuses didn’t have an elevated risk in response to COVID-19 infections. That was wrong, and those who are pregnant are at greater risk. https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/pregnancy-breastfeeding.html
10) Kids are far less likely to get seriously sick. But we still don't know how much they spread the disease, why they seldom become seriously ill, or why a small but growing number have been hospitalized for a coronavirus-linked syndrome called MIS-C. https://www.buzzfeednews.com/article/zahrahirji/kids-coronavirus-kawasaki-disease-rare
11) We still don’t know how long immunity lasts, but there is reason to be hopeful: We know antibodies last for at least several months, immunity to other coronaviruses lasts even longer, and relatively few reinfections have been reported so far..
12) New mutations of the coronavirus do appear. Scientists are monitoring them, and so far think that our current vaccines will remain effective against them.
13) There is a large racial disparity in deaths. Black, Latinx, and Native American people have died in outsized numbers, at rates 2.6 to 2.8 times higher than white Americans. https://www.cdc.gov/mmwr/volumes/69/wr/mm6942e1.htm#contribAff
As the virus continues to spread, we'll continue to track and write about it. See the latest figures: https://www.buzzfeednews.com/article/peteraldhous/coronavirus-deaths-cases-world-us-maps-charts