World Surpasses 400 Million Confirmed Covid Cases

The world surpassed 400 million known coronavirus cases on Tuesday, according to the Center for Systems Science and Engineering at Johns Hopkins University, just one month after reaching 300 million. It is a staggering increase driven by the highly transmissible Omicron variant as governments and individuals worldwide wrestle with how to confront the next stage of the pandemic.

It took more than a year for the world to reach 100 million confirmed infections: The first cases were identified in late 2019, and the 100 millionth in January 2021. It took only seven months to double that number, and now six months to double it again. Daily case counts have begun to decline, but there have been an average of more than 2.7 million infections reported every day.

The actual number of cases is undoubtedly higher, and probably drastically so. Many at-home rapid test results are never officially reported, and not all infected people get tested because they may lack access, have no symptoms or choose not to.

As the virus has mutated, almost five billion people have received at least one dose of a coronavirus vaccine, and research indicates that vaccines still offer protection against the worst outcomes. The current, dominant form of the virus — Omicron — is less likely to lead to hospitalization or death, so case counts on their own have become less useful as a metric, at least in places with higher rates of vaccination or prior infection. In New York City, for example, cases peaked 541 percent higher this winter than last, but deaths rose much less, peaking 44 percent higher than last winter.

But scientists have cautioned that protection against infection may wane over time, and future variants may be better able to sidestep our defenses.

Still, many governments have loosened restrictions as Omicron-fueled surges in many places have declined. Australia will soon reopen its borders to vaccinated visitors. Sweden is lifting most of its pandemic regulations, following in the footsteps of Denmark and Norway. Just this week, the governors of California, Connecticut, Delaware, New Jersey and Oregon said they would end statewide indoor mask mandates, some of which applied to schools and others to public places.

Dr. Céline Gounder, an infectious disease expert and epidemiologist at Kaiser Health News, said in an interview on Tuesday that whether such relaxations were appropriate or premature depended on local context, including vaccination rates, number of infections, and hospitalization rates relative to hospital capacity.

Within the United States, “if there’s anywhere that’s in a position to dial back on mitigation measures, it would be parts of the Northeast,” Dr. Gounder said. But she added that she was surprised at the decision to do so statewide in California, where circumstances vary greatly at the local level.

The moves reflect the profound exhaustion people are experiencing two years into the pandemic, and an understanding that the coronavirus is here to stay in some form. But what that looks like remains unclear. “The virus will become endemic” is a truth broadly accepted by people who disagree on what the word even means.

Endemicity can, but does not necessarily, mean a mild threat: The common cold is endemic, but so is malaria in many parts of the world. The coronavirus will probably end up posing a greater or lesser threat in different places, depending on vaccination rates and other factors. New variants could further complicate the picture, especially with billions of people around the world still unvaccinated.

Only 11 percent of people in low-income countries have received a dose of a coronavirus vaccine, compared with 78 percent in high- and upper-middle-income countries, according to the Our World in Data project at the University of Oxford. Africa has the slowest vaccination rate of any continent, with just 15.4 percent of the population receiving at least one dose. Some people with disabilities, chronic illnesses or weakened immune systems remain vulnerable despite vaccinations.

And the coronavirus continues to take a devastating toll, including in the United States, where the virus has killed at far higher rates than in other wealthy nations.

More than 5.7 million people worldwide have died of the virus, including more than 900,000 in the United States alone. On average, the United States is reporting 2,598 new deaths a day, the equivalent of a disaster worse than Pearl Harbor every day. Globally, 10,900 people a day are dying from Covid-19.

“We’re concerned that a narrative has taken hold in some countries that because of vaccines, and because of Omicron’s high transmissibility and lower severity, preventing transmission is no longer possible and no longer necessary,” Dr. Tedros Adhanom Ghebreyesus, the director general of the World Health Organization, said last week. “Nothing could be further from the truth.”