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Coronavirus cases spiking in 45 US states. What that means for a second wave

With rates of infection rising faster in some places now than at the start of the pandemic, some states are racing to roll back reopening plans -- others, not so much.

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Most US states and countries are reopening to some degree. Experts warn that coronavirus infections could begin to increase as a result.

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For the most up-to-date news and information about the coronavirus pandemic, visit the WHO website.

As confirmed coronavirus cases top 10.5 million globally and as many as 45 US states are seeing increases in new case numbers, the question becomes even more poignant: Is this the second wave health experts warned of since the pandemic began?

According to the top US infectious disease expert, Dr. Anthony Fauci, no, this is not the second wave. The virus is actually still very much on its first pass. So, what's going on?

In the US, the coronavirus's curve hadn't even been completely flattened yet when a wave of new cases began to build momentum at the end of June. Now, Fauci predicts we could see as many as 100,000 new cases per day in the coming weeks. The reason? Loosened lockdown restrictions and the widespread flouting of social distancing and face mask guidelines, he said.

We examine what experts say a second wave of coronavirus might look like, when it could happen, the difference between a "wave" and a "spike" and more. Please note, this story provides an overview of the current discussion, and updates frequently in light of new and changing information provided by health officials, global leaders and the scientific community. It is not intended as a medical reference. 

A second wave of coronavirus cases? The latest news

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Why are there more confirmed coronavirus cases now?

There are several explanations for why coronavirus cases are rising now. A greater portion of the population is being tested, for example, so there are more positive test results in total. However, an analysis by ProPublica in late June demonstrates that the rate of positive results is outpacing the rate of expanded testing, meaning testing alone can't be blamed for the recent surge. The need for more hospital beds in affected states like California, Arizona and Texas also suggests that the overall caseload is rising in addition to the greater number of positive results.

Loosened lockdown restrictions and social gatherings where people are closer than the recommended six feet could also contribute to new cases. And the virus is now circulating in new populations, for example, 20- to 30-year-olds. Experts believe this all contributes to the rising numbers. 

Could there be another lockdown?

It's already starting to happen. So far at least 19 US states have either paused or reversed their reopening plans in response to recent surges in coronavirus cases. For example, Texas and Florida -- two of the first states to lift lockdown restrictions -- recently walked back the reopening of restaurants and bars, which now have had to close their doors for a second time.

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Businesses from restaurants to retail are opening, which brings people into closer contact. 

Sarah Tew/CNET

In other parts of the world that have experienced a surge of coronavirus infections after lifting lockdown restrictions, many such measures have been reinstated. In June, Germany extended its lockdown in North Rhine-Westphalia by a week and the UK has imposed a local lockdown in the city of Leicester, both due to increases in coronavirus cases.

Until there's an effective vaccine, it's possible that different parts of the US and the world will see fluctuating degrees of lockdown as governments adjust their response in the ongoing battle against the coronavirus.

What are the effects of reopening the economy on coronavirus cases?

For public health and medical experts, the correlation seems high, even "totally predictable." Others posit that in addition to people coming into close proximity, the virus might be "catching up" to populations that had previously been uninfected.

Public health experts have warned that it's too soon to reopen businesses and resume social activities, such as going to the lake or beach and visiting amusement parks, even with limited capacity. Others have argued that cities must reopen to keep the economy afloat, and that protective health measures will curb coronavirus transmission in restaurants, schools, malls and on planes. 

Closed Parks due to Coronavirus

Could life shut down again? It's already happening to some degree.

Jessica Dolcourt/CNET

The Centers for Disease Control and Prevention have also released guidelines to help local governments identify phases for reopening, and interim suggestions for restaurants, schools and industry.

Part of the problem is that the full extent of short- and long-term effects of the coronavirus and the COVID-19 disease it causes are still unknown, including how long you may be immune after you recover and if it's possible to become reinfected. Most experts agree that until we have an effective coronavirus vaccine, the only way to slow the spread of the virus is by taking precautions like social distancingwearing face masks in public and washing hands correctly and frequently.

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Do we still expect a second coronavirus wave this fall?

Most public health experts -- including Fauci and the Director of the CDC, Dr. Robert Redfield -- have said they anticipate a big uptick to happen this fall or winter. The White House has admitted it's preparing for the possibility. A new model also suggests an increase in coronavirus-related deaths this September, CNN reported.

However, part of that prediction hinged on the virus slowing down over the summer, which appears not to be happening. 

Much of the attention aimed at fall has now shifted to concern over the possibility of two potentially lethal viruses circulating at the same time. Redfield told Time Magazine in June, "The real risk is that we're going to have two circulating respiratory pathogens at the same time," referring to both the coronavirus and the seasonal flu.

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Different parts of the country are lifting lockdown orders at their own pace, including deciding when to open nonessential businesses.

Angela Lang/CNET

What's a 'second wave' anyway? Can there be more?

Generally speaking, a "wave" in a pandemic is a period of increasing disease transmission following an overall decline. In the US and many parts of the world, after peaking in April, new cases declined modestly then plateaued through most of May before starting to spike again in late June. If and when infection rates have declined substantially across the board, when they begin to climb again, that will indicate the next or "second wave." The longer the pandemic goes on, the more waves are likely to occur.

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A wave might be made of smaller ripples or 'peaks'

The coronavirus pandemic hasn't affected all parts of the US in the same way or at the same time. Cities and states went into lockdown and quarantine at different times, and that's also how the country is starting to get out of it, with different areas easing restrictions in phases and at their own pace.

Some health experts have warned the lack of a unified reopening plan might help spread the coronavirus and could actually fuel a second wave as people travel from the hardest hit areas to places with far fewer infections. Ali Khan, a former CDC official, said a second wave might comprise many simultaneous, smaller outbreaks that, taken together, seem more like a singular wave.

Spikes in new coronavirus cases have already been documented in areas emerging from lockdown. Wisconsin, for example, experienced its biggest single-day increase in new infections and deaths exactly two weeks after the state Supreme Court overturned the governor's stay-at-home order. Georgia, which was one of the first states to start lifting lockdown orders, is beginning to see an uptick in new cases after several weeks of plateau.

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Could a second wave be worse than the first?

If there is a second coronavirus wave, the severity of the outbreak would depend on multiple factors, including how well people maintain social distancing and how many people wear face masks. The widespread availability of tests might also play a role, in addition to contract tracing for anyone who tests positive. 

For example, a study and computer model developed under Dr. De Kai, a computer scientist with appointments at both the University of California at Berkeley and Hong Kong University, proposes that if 80% of the population wore face masks in public, coronavirus transmission rates would plummet (PDF) to about 8% compared to wearing no masks.

Basically, the more measures there are in place to help reduce disease transmission -- and the more effectively those measures are followed -- the lower the infection rate may be the second time around, according to the computer model. 

Other factors that could come into play are any potential genetic mutations in the coronavirus that could make it more or less transmissible, the development of an effective vaccine, the development of safe, effective treatments for the COVID-19 disease and the ability to test a large percentage of the population, even people who don't appear to be sick.

Perhaps the most pressing questions of all are what a second wave of coronavirus might mean for you. Here's how we think life will look after quarantine ends as the public braces for a second wave. If you do have to leave the house, here are some practical ways to stay safe when you go out. Finally, don't unlearn all the good habits you've developed during the pandemic -- like frequently washing your hands.