A light at the end of the coronavirus tunnel? 6 signs to look for

There are encouraging signs that the most intensive phase of our battle against the novel coronavirus is succeeding. The number of new COVID-19 cases nationally is tapering downward and some initial studies have shown that far more people were infected but had mild or no symptoms at all.

That doesn't mean we can - or should -- declare victory and go home. We're far from being able to return to "normal." But it's nice to see what appear to be a few green shoots of encouraging data.

Public health officials and epidemiologists like me are examining the ever-higher resolution data picture of the virus's spread and effects. Here are six indicators I'm looking at to help determine if we're seeing the first light emanating from the end of this dark tunnel.

1. Are the patterns from increased COVID-19 testing consistent with what we've seen in other countries?

We've been flying pretty blind with very low testing rates in the U.S. (about one million tests per week in a nation of 330 million people). We need more in order to have a clearer picture of the actual scope of our COVID-19 cases. Currently, about 20% of Americans tested have been positive, which would reflect an ongoing epidemic. But countries that have tested more citizens per capita are generally showing lower rates of positive cases -- Australia is at about 1.5%, South Korea 2%, Iceland 4%. If we see our rate of positives heading more toward those numbers, it will suggest our rates of testing are starting to generate sufficient data to guide our subsequent responses.

2. Does increased serology testing confirm more people than we thought have had the virus?

The early signs from COVID-19 serology testing - which looks at blood and bodily fluids to track a person's immune system responses - is that a lot more people have been exposed to the virus than we thought. A new study from Santa Clara suggests that 40 to 80 times more people may have already had the virus than we estimated, though the methodology has been widely criticized. Should those results hold true in longitudinal studies, it will be good news and potentially indicate that we are further along in the epidemic than we had realized.

3. Does real-time health data continue to show the number of people with new COVID-19 symptoms decreasing?

Given the severe lack of testing, we look to track symptoms of illness - in epidemiology we call that "syndromic" data - to confirm that we have passed the peak of the epidemic. These data include the Centers for Disease Control and Prevention's traditional flu surveillance efforts that track people interacting with the health care system. My work over the past few years has been focused on how to gather and employ big data - including seemingly unfiltered or crowd-sourced data - that helps shine a light on disease outbreaks. We want to see reports from sites like COVID Near You (which my fellow medical school faculty members and I helped build and launch) falling, telling us similar stories to what formal testing is.

4. Is the health care system prepared for the influx of cases?

In the nation's coronavirus hot zone - metropolitan New York - the health care system and hospitals appear to have bent but not broken under the weight of COVID-19. That's great news. We need that kind of evidence of success from other geographies that have yet to experience peak activity - enough ICU beds, enough personal protective equipment, enough ventilators and adequate staffing levels. We've recovered from some earlier frightening gaps, and if we follow a similar or better pattern as COVID-19 cases peak across the country, it will be a very positive sign.

5. Are rural communities able to handle their unique challenges without being overwhelmed?

The coronavirus presents a big challenge in rural areas across the U.S. To rural residents' benefit, lower population densities and a more home-based lifestyle should generally help tamp down the spread of the virus. On the other hand, rural health care systems are smaller and more isolated. Rural populations also tend to be poorer and more prone to some underlying conditions that make COVID-19 more lethal. We need and want these communities to move through case peaks successfully.

6. Will we continue to socially distance and keep hygiene standards high?

No one likes living under restrictions, let alone full lockdowns. We want to be able to move the country toward a gradual easing of the "do nots" and "may nots" that have become part of our lives. But until we're much farther down the road toward herd immunity or the implementation of a vaccine, we're still going to need to exercise great caution. That means intense personal hygiene regimes need to stay with us for the foreseeable future. We'll still need to avoid large crowds and unnecessary close-quarters situations. And we need to continue to push for innovative ways to expand our public health capacity to test, trace and isolate so we have weapons for controlling spread when incidence declines. If our willingness to do so stays high, these hopeful points of light should grow brighter.

We're not out of the COVID-19 tunnel yet by any means, but we're headed in the right direction. The next few weeks of intensive testing and data collection will help us know how far we've still got to travel.

Dr. John Brownstein is a Chief Innovation Officer at Boston Children's Hospital and Professor of Pediatrics at the Harvard Medical School. He is also an ABC News contributor.