The pandemic keeps changing, but these principles can guide your thinking through the seasons to come.

In a Times simulation, we modeled Delta-driven Covid outbreaks in two communities, one with a high vaccination rate and another with a low rate. Their levels of serious illness and death were starkly different.

Infections in vaccinated Americans are rare, compared with those in unvaccinated people, the document said. But when they occur, vaccinated people may spread the virus just as easily.

In communities with growing caseloads, vaccinated and unvaccinated people should return to wearing masks indoors in public areas, health officials said.

To hear an audio spoken word version of this post, click here.   One of the favorite parts of my job is thinking about issues in ways other people often do not. That might include identifying where consensus may be wrong (Inflation, Urban Exodus, Insurrections) or market values responding differently than expected. Even for issues…Read More

The highly infectious version of the virus ‘is gaining ground,’ one Southern governor warned amid an uptick of recorded infections in almost every state.

One dose of vaccine is not enough to protect against the Delta and Beta variants, new research suggests, and even people who have had Covid-19 should be immunized.

Israel reported that the Pfizer vaccine was 64 percent effective against the Delta variant. Other studies suggest a higher rate.

A social media post claims that COVID-19 vaccination is unnecessary since unvaccinated people have "escaped every single/>

The Delta variant is more transmissible than previous strains, according to MCPH Executive Director Jeff Kuhr.

State public health officials expect that more than half of Colorado's COVID-19 cases are tied to the 'highly contagious' Delta variant.

The highly transmissible variant remains the "greatest threat" to the U.S. coronavirus response, officials warn.

A cluster that began with an airport limousine driver has jumped to nearly 100 cases, with dozens more expected over the coming days.

Pfizer and AstraZeneca work together well in a two-dose vaccination schedule; so do three doses of AstraZeneca, researchers find in separate studies.

A new and slightly changed version of the Delta coronavirus variant is spreading in a number of countries including the United Kingdom, United States and India, health officials say.

In other developments, the CDC added Delta as a variant of concern and issued its first guidance on 'long COVID'.

The World Health Organization has implemented a new system to name variants of COVID-19 that use Greek letters instead of country names to avoid stigmatizing the regions