Less than a year and a half ago, the world was blissfully, dangerously ignorant of the existence of a coronavirus that would soon turn life on earth on its head.

In the 16 months since the SARS-CoV-2 virus burst into the global consciousness, we?ve learned much about this new health threat. People who contract the virus are infectious before they develop symptoms and are most infectious early in their illness. Getting the public to wear masks, even homemade ones, can reduce transmission. Vaccines can be developed, tested, and put into use within months. As they say, where there?s a will, there?s a way.

But many key questions about SARS-2 and the disease it causes, Covid-19, continue to bedevil scientists.


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