Thread by @nytimes

Scientists around the world are racing to understand the Omicron coronavirus variant. There is still a lot of uncertainty, but we asked experts four big questions about it. nyti.ms/3rKwdzJ

Does Omicron spread faster than earlier variants? Yes, in all likelihood. nyti.ms/3rKwdzJ

A bigger unknown is why the Omicron variant is spreading rapidly. Here are two plausible answers. nyti.ms/3rKwdzJ

Is Omicron more severe than earlier variants? Probably not. But some scientists think it’s simply too early to know as the world has been monitoring Omicron for less than two weeks. nyti.ms/3rKwdzJ

So far, hospitalization and death rates in South Africa have not soared even as cases have. Intriguingly, patients are reporting less loss of taste and smell. nyti.ms/3rKwdzJ

Are vaccinated people protected from Omicron or not? There is still no sign that it will cause a significant share of vaccinated people to get severe versions of Covid. nyti.ms/3rKwdzJ

But seemingly mild Covid infections can prove deadly for vulnerable people, and immunity seems to be waning over time. Experts are encouraging people to get vaccinated, even if they’ve had Covid, and getting boosted, if eligible. nyti.ms/3rKwdzJ

Do Covid tests — including both PCR tests and rapid at-home tests — still work? Yes, based on the signs so far. nyti.ms/3rKwdzJ

The bottom line is that early signs may prove misleading, and we will know more about Omicron within a few weeks.

Read experts’ full explanations of what they know so far here: nyti.ms/3rKwdzJ