COVID-19

COVID-19 was first identified in December 2019 and was declared a global pandemic within months. While research on the disease and its outcomes is still in relatively early stages, the pandemic set off an unprecedented level of scientific collaboration and discovery.

Photo by Alisha Jucevic, Reuters.

10 million deaths due to COVID-19 have gone unreported.

16.5K deaths were reported daily at the peak of the pandemic in January 2021.

50% of the world was fully vaccinated against COVID-19 at the end of 2021.

63% of those with long COVID during the first two years of the pandemic were female.

Key findings

We began forecasting the trajectory of the COVID-19 pandemic in early 2020 to help hospitals and policymakers plan how to allocate resources. Now, we estimate cases, deaths, and disability due to COVID-19 as part of the Global Burden of Disease study.

Immunity from a past COVID-19 infection fades over time.

Our research supports the need for annual vaccines. While immunity after an infection is initially strong, it begins to drop after about 6 months and can provide as little as a third of its previous protection after a year.

Women are twice as likely as men to develop long COVID.

On average, long COVID lasts nine months for someone who was hospitalized for their illness and four months for someone who was not.

15% of those with long COVID symptoms three months after becoming infected with COVID continued to experience symptoms even at 12 months.

Read the article on long COVID

US states that imposed more vaccine and mask mandates had lower infection rates.

However, there were trade-offs that came with those decisions. While states with more restrictions did not experience worse economic outcomes, they did have lower rates of employment and lower student test scores.