Before COVID-19, there was tuberculosis. Twentieth century British physician Thomas McKeown controversially proposed that the sharp declines in infectious disease death rates in the late 1900s were due to improved economic and social conditions – not medical and public health measures like antibiotics and improved sanitation.

His theory was later partly discredited. But the central question behind it – whether medical interventions or social factors make the biggest impact on infectious diseases – remains relevant in the current pandemic.

When COVID-19 first arrived in the U.S., the only tool public health officials had to stop its spread was behavior change through lockdowns, social distancing and face masks. With vaccines, the tide seemed to turn. But with new variants, waning immunity and ongoing vaccine hesitancy, the pandemic is still far from over.

So which are more successful at driving down rates of disease and death – social behaviors or medical technologies?

As an infectious disease and social epidemiologist, I have been particularly interested in how new medical technologies affect existing health disparities. I believe that understanding the interplay between behavior and technology will be key to surviving the pandemic and emerging as a stronger society.

Do technologies help or make things worse?

Biomedicine has clearly played a critical role in mitigating COVID-19. Less than a year after discovering the virus that causes COVID-19, researchers were able to develop multiple vaccines that are highly effective in preventing severe infection and transmission from most variants. They’re also likely to reduce the risk of long COVID-19, the ongoing symptoms that can persist for months after initial recovery. COVID-19 vaccines are estimated to have saved almost 140,000 lives in the U.S. in the first five months of 2021.

There has also been remarkable medical progress in other arenas. Even though antivirals are notoriously difficult to manufacture, there are finally options for treating COVID-19. Merck’s molnupiravir cuts hospitalization risks for adults in half, and Pfizer’s paxlovid has 89% efficacy at preventing hospitalization and death. Additional treatments are expected in the coming months.

Researchers have also developed and scaled up a variety of innovative diagnostic technologies. These range from using PCR tests to predict the trajectory of the pandemic to implementing blood tests that can simultaneously measure antibody levels against COVID-19 and other pathogens for quicker diagnosis.

Collaboration across both public and private sectors has also been fairly unprecedented. Large-scale government funding has aided these efforts. The U.S. National Institutes of Health’s Rapid Acceleration of Diagnostics, or RADx, initiative, for example, has worked to contain outbreaks in schools by providing COVID-19 test kits across the country.

Social factors as drivers of health

Despite these technological advancements, the COVID-19 pandemic has illuminated long-standing health disparities. In 2020, Latino and Black people died from COVID-19 at a rate almost three times higher than white people.

Systemic structural and social inequities are some of the reasons behind these disparities in the U.S. For example, communities of color are disproportionately represented in essential occupations that are at the front lines of potential COVID-19 exposure. In addition, Black and Hispanic Americans have higher rates of obesity, hypertension and type 2 diabetes, known risk factors for severe COVID-19 complications. Children in communities of color also experienced the death of a primary caregiver at a rate up to 4.5 times higher than non-Hispanic white children.

Technologies intended to improve health care can themselves exacerbate health disparities. This results in a digital divide where certain populations continue to have poor health despite technological improvements. For example, the safety and convenience of remote videoconferencing is a privilege unavailable for those who need to go to public workspaces to access these technologies.

This divide extends to medical devices used in routine care. Oximeters that measure oxygen levels in the blood tend to produce inflated results for people with darker skin because they were calibrated in clinical trials with mostly white participants. This racial bias may result in denial of care if someone with darker skin gets a normal reading despite actually having dangerously low oxygen levels.

Health disparities persist despite technology

These inequities are often derived from ongoing historical biases and discrimination.

Socioeconomic status, occupation and economic mobility are primary drivers of unequal health outcomes. In 2020, 5.4 million laid-off workers became uninsured in just four months. In 2019, 55% of retail and food workers at large firms didn’t have access to paid sick leave. Many immigrants, whether undocumented or legal U.S. residents, are likely to avoid the health care system due to fear of deportation and limited insurance coverage and public assistance.

Difficulty parsing through health information is another factor. In addition to abundant misinformation about COVID-19, nearly 9 in 10 adults struggle with health literacy. A July 2020 study found that Black men were less likely to know about COVID-19 symptoms and how the virus spreads than white men. For some groups, limited English proficiency and cultural beliefs are barriers to health communication.

Even more critical is distrust in the medical system. Historical unethical experimentation and everyday racism have led to a lack of confidence in scientists and clinicians among vulnerable populations. Two-thirds of Black adults believe the government can rarely or never be trusted to look out for the interests of their community.

Conversely, that COVID-19 hospitalizations and deaths disproportionately affect lower-income populations and communities of color reinforces the need for greater diversity in clinical research participants. Over 80% of participants in the Pfizer-BioNTech COVID-19 vaccine trial identified as white. Having clinical trials that reflect the patients who will be treated ensures that the drug will work for all and encourages confidence among those communities.

The importance of social factors in health

While technology has greatly improved U.S. pandemic response, broader societal ills continue to impede the nation’s ability to control COVID-19.

The McKeown debate exposes a common misconception that improving health is a binary: a choice between improving social conditions or developing new technologies and medicines. But a growing body of research shows that social factors, or the conditions where people live, work and play, are key to health outcomes.

There are numerous strategies that can increase health equity in this time of crisis. These include tackling food insecurity, flexibility in work conditions, targeted vaccine initiatives and culturally competent health care. Engaging with communities as partners in health also advances the nation’s ability to cope during a crisis.

Nobel prize-winning economist Amartya Sen hypothesized that increases in life expectancy in the 20th century occurred in periods marked by a strong emphasis on social sharing and public provision of health care. To me, it’s clear that the time has come to invest not just in new technologies and medical treatments, but also in communities.

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Eyal Oren, Professor of Epidemiology, San Diego State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Alongside a lingering global pandemic, the year 2021 was filled with climate disasters, some so intense they surprised even the scientists who study them.

Extreme rainstorms turned to raging flash floods that swept through mountain towns in Europe, killing over 200 people. Across Asia, excessive rainfall inundated wide areas and flooded subway stations in China. Heat waves shattered records in the Pacific Northwest, Europe and the Arctic. Wildfires swept through towns in California, Canada, Greece and Australia. And those were only a few of the extremes.

In the U.S. alone, damage from the biggest climate and weather disasters is expected to total well over US$100 billion in 2021.

Many of these extreme weather events have been linked to human-caused climate change, and they offer a glimpse of what to expect in a rapidly warming world.

In the U.S., something in particular stood out: a sharp national precipitation divide, with one side of the country too wet, the other too dry.

As a climate scientist, I study the impact of global warming on precipitation and the water cycle. Here’s what happened with precipitation in the U.S. in 2021 and why we’re likely to see similar scenarios in the future.

The east-west weather divide

The eastern U.S. weathered storm after storm in 2021. Record rainfall in Tennessee triggered deadly flash flooding in August. The remnants of Hurricane Ida merged with another front days after the hurricane hit Louisiana and became so intense they set rainfall records and flooded subway stations and basement apartments in New York and Pennsylvania, with devastating consequences.

Almost the entire West, meanwhile, was in some stage of drought, helping to fuel wildfires that swept through forests and towns.

This kind of east-west weather divide can be enhanced by La Niña, a periodical phenomenon fueled by Pacific Ocean temperatures that tends to leave the Southwest drier than normal and the North and much of the eastern half of the U.S. wetter.

But something else is going on: Global warming fuels both dryness and extreme rainfall.

3 impacts of global warming on rainfall

Three things in particular happen to precipitation when the planet warms.

1) Global warming leads to more overall precipitation.

Higher temperature increases evaporation from Earth’s surface. It also increases the atmosphere’s capacity to hold moisture at a rate of about 7% per degree Celsius that the planet warms. With more moisture evaporating, global precipitation is expected to increase, but this increase is not uniform.

2) Global warming leads to more intense precipitation.

With higher temperature, more moisture is needed to reach the condensation level to form precipitation. As a result, light precipitation will be less common. But with more moisture in the atmosphere, when storm systems do develop, the increased humidity leads to heavier rainfall events.

In addition, storm systems are fueled by latent heat – the energy released into the atmosphere when water vapor condenses to liquid water. Increased moisture in the atmosphere also enhances latent heat in storm systems, increasing their intensity.

Research shows that both the frequency and intensity of heavy precipitation events has increased since the 1950s over most land areas.

3) Global warming tends to make wet places wetter and dry places drier.

Precipitation is not distributed evenly over the planet because of the global atmosphere circulation pattern. This global circulation brings moisture to places where winds come together, such as the tropical regions where we find most of the world’s rainforests, and away from places where winds diverge, such as the midlatitudes where most world’s deserts are located.

Assuming no significant changes in global wind patterns, increases in evaporation and moisture will mean more moisture is transported from dry areas to wet areas and into the storm tracks at higher latitudes. Global warming could also potentially change the global circulation pattern, causing a shift in the world’s wet and dry regions.

Mountains, moisture and the east-west divide

These dynamics are also affected by local conditions, such as the shape of the land, the types of plants on it and the presence of major water bodies.

The western U.S., with the exception of the West Coast, is dry in part because it lies in the rain shadow of mountains. The westerly wind from the Pacific Ocean is forced upward by the mountain ranges in the West. As it moves up, the air cools and precipitation forms on the windward side of the mountains. By the time the wind reaches the leeward side of the mountains, the moisture has already rained out. As the wind descends the mountains, the air warms up, further reducing the relative humidity.

Higher temperature in areas like these where the moisture supply is already limited means less humidity in the air, leading to less rain. Higher temperature and less precipitation would also reduce snow packs in the mountains and cause earlier melt in spring. All these changes are likely to increase aridity in the West.

The eastern U.S., on the other hand, receives abundant moisture from the North Atlantic and the Gulf of Mexico carried by the easterly trade wind. With abundant moisture supply, increasing temperature means more moisture in the atmosphere, leading to more precipitation and stronger storms.

This is what years of precipitation records show and what is projected for future precipitation based on climate models. Both show a decrease in annual precipitation in the West, likely meaning more long periods of drought, and an increase in the East with global warming.

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Shuang-Ye Wu, Professor of Geology and Environmental Geosciences, University of Dayton

This article is republished from The Conversation under a Creative Commons license. Read the original article.