Eight months in, California is containing COVID-19 as other states spike. Here’s why.

SAN JOSE, Calif. — Eight months into the coronavirus pandemic, California has become a rare case: a state that has contained the transmission of COVID-19 and isn’t experiencing another surge — yet, at least.

Nationwide, daily infections are up one-quarter in the last two weeks, and the country just reported its most in a single day since July. Lightly populated North Dakota is seeing 85 new cases a day per 100,000 residents over the last two weeks. California? Ten new cases per 100,000, up just 2% in two weeks.

The reasons, health experts say, are made clear by a stroll through San Francisco. Pedestrians are masked and passing each other at acceptable social distances. Painted circles partition off small groups at one of the city’s most popular parks. Posters stapled to signposts once hawked live music; now, they advertise masks.

Every city could be San Francisco, and every state like California, these experts say. SARS-CoV-2 has proved to be a complex and mysterious virus, but eight months since it landed on our shores, the science seems clear on a simple way to contain it.

“If you social distance and you wear masks, you decrease the cases dramatically,” said Dr. John Swartzberg, an infectious-disease expert and professor emeritus at UC Berkeley. “A culture that accepts the science and follows it is going to do better.”

On an epidemiological basis, Swartzberg’s argument is sound, though people across the country continue to argue over whether the restrictions are exacting too great an economic and social price. Even in California, respected leaders say some aspects of the restrictions — shifting schools almost entirely to distance learning, for one — have gone too far.

Yet as the debate continues, a third wave of coronavirus cases is sweeping across the Midwest even as this summer's surge through the South has hardly begun to relent. Even in parts of the Northeast, which successfully vanquished the virus after a devastating initial wave in the spring, transmission is on the rise.

There is good news: Death rates haven't jumped in tandem, as doctors grow better at treating the sick. But with more infections and more fatalities than any other country in the world, and more than 20 states reporting record new case numbers over the past week, the outlook in the U.S. is grimmer than it could have been.

Why? Before the surge, and continuing throughout it, many states have been loosening restrictions meant to prevent the virus from spreading.

» READ MORE: Fauci ‘absolutely not’ surprised by Trump’s COVID-19 diagnosis

In Texas, Gov. Greg Abbott has reopened bars and allowed fans at sporting events. In Florida, Gov. Ron DeSantis has lifted all restrictions.

In the spring, it was California shaking off its shutdown, then suffering from a surge in June. But the state learned lessons from its own initial attempt to reopen, which propelled it to the height of its infection rate about six weeks later.

Now Gov. Gavin Newsom and state health officials have implemented a reopening system that health experts say is working.

Each week, counties are evaluated on their per-capita infection rate and positivity rate, then placed into one of four tiers, which determines which sectors can operate and at what capacity.

But the rules are strict. In the Bay Area, with the lowest coronavirus risk of any major population center in California, many counties are finally able to allow indoor dining again, but only at 25% capacity. Even so, some are opting not to.

"I think we need to ride it the way we're riding it right now. I think it's working," said Dr. George Rutherford, an epidemiologist at UC San Francisco, who also said he is "baffled" by the opposite approaches being taken in other states.

"What the hell are they thinking?" he added.

A recent study from the Centers for Disease Control and Prevention showed the dramatic impact public health orders made in a different state that has had its ups and downs, Arizona.

» READ MORE: COVID-19 cases are rising fast in Pa. and NJ., but hospitals are not burdened — yet. Here’s why.

At first, Gov. Doug Ducey took the same step as Abbott of Texas and some other governors and prohibited local jurisdictions from enacting and enforcing their own health orders. Cases went up 151% after the state's initial stay-at-home order was lifted. But then they fell by 75% after prevention tactics were reimplemented, according to the CDC study. Today Arizona's case rate roughly mirrors California's.

In Wisconsin, in contrast, the case rate over the last two weeks has been six times that in California. Earlier in the pandemic, the Wisconsin Supreme Court struck down Gov. Tony Evers' statewide health orders, and since then the state has struggled to control transmission.

"These things are there for a reason," Rutherford said of the restrictions. "And the reason is to prevent cases and to prevent deaths."

In Texas, some counties began to reopen bars last week after Abbott announced the end of a statewide closure. For the entire preceding month, indoor dining and other businesses had already been allowed to operate at 75% capacity.

Catherine Troisi, Ph.D., an infectious disease epidemiologist at UTHealth School of Public Health in Houston, could visit a bar or dine at a local restaurant. She still opts for takeout and delivery, though she did make one recent exception for an outdoor dining excursion.

Texas is seeing a rise in cases, positivity rate and hospitalizations, Troisi said.

"You know, we could certainly keep the number of cases down, but because it's become a political issue, some people aren't willing to do it," Troisi said, referring to the public health measures.

On top of that, people everywhere are suffering from "pandemic fatigue," Troisi said.

One statistic illustrates the shortcomings of the U.S. pandemic response: Despite making up just over 4% of the global population, Americans account for about 20% of the worldwide deaths from COVID-19.

Last month, shortly after the country crossed the grim 200,000-death milestone, Dr. Bob Wachter, the chair of medicine at UCSF, offered a stark contrast between the outcomes locally and nationally.

If everyone in the U.S. were infected and died of the virus at the same rate, per capita, as in San Francisco, he said, more than 136,000 lives would have been saved. Since that analysis, another 18,000-plus Americans have died.

While it's true that any state, county or city could take the same steps as California and the Bay Area, it did enter this health crisis with one unique advantage. It was at the center of the last one.

San Francisco led the global response to the AIDS crisis. Not only did that garner the goodwill of the public for ensuing epidemics, but many of the people on the front lines in the '80s are also now in positions of leadership around the city.

"One of the things we learned in the AIDS epidemic was that this trifecta of public health department leadership, academic centers and the community all working together," Dr. Diane Havlir, another epidemiologist at UCSF, said at a recent Grand Rounds hosted by the school. "That is the magical formula to respond to a pandemic."

That public trust has paid off in one of the country's highest rates of mask usage. A new study from Carnegie Mellon University showed the highest self-reported mask usage in California and the Northeast. In both places, more than 90% of people reported wearing masks either most or all of the time while in public when surveyed between Sept. 8 and Oct. 7.

The lowest rates of mask usage were in the Midwest and the South, where in most states between 50-60% of people reported wearing one.

"We don't like the government telling us what to do," said Troisi, the University of Texas epidemiologist.

A number of factors made this “just about … the worst time in American history” for a global health crisis, Swartzberg said — not least of which is the country’s diminishing trust in the government.

In the Bay Area, however, "we have the opposite," Swartzberg said.

Of course, there's no guarantee Californians won't grow impatient with the current restrictions, pushing to end them or resolving to ignore them. Cases could spike again. But so far the state seems cautious in the face of its recent success.

Now, some schools are preparing to return to in-person learning, but many others are resisting. Diners congregate — though not too closely — in newly erected sidewalk cafes, where, yes, many do put their masks on between bites.