Test negative studies have been used extensively for the estimation of COVID-19 vaccine effectiveness (VE). Such studies are able to estimate VE against medically-attended illness under certain ...

WASHINGTON, DC - MARCH 5: Jayanta Bhattacharya, U.S. President Donald Trump's nominee to be Director of the National Institutes of Health, speaks at his confirmation hearing before the Senate ...

On Wednesday, the White House reported that President Joe Biden had twice tested negative for Covid-19. The news was welcome but expected. When Biden first tested positive a few days ago, his having ...

Risk management of new coronavirus infections has become a significant public health issue. Isolation of symptomatic individuals was insufficient to control the spread of infection, because some ...