While the latest research shows that COVID-19 is primarily caused by airborne transmission of the SARS-CoV-2 virus, there is still some risk that people may be exposed to the virus from contact with contaminated surfaces. Therefore, CDC still recommends routine cleaning and disinfection of potentially contaminated surfaces. Businesses and institutions, including some airlines, schools, and transit agencies, have been using electrostatic sprayers to clean and disinfect large surface areas quickly and effectively that are frequently touched by many people. EPA researchers, at the request of stakeholders, were asked to evaluate how these sprayers worked.
The 2021 edition of the bp Statistical Review of World Energy was published last week, which means it’s time for my annual commentary. This year’s release is the 70th anniversary edition; as always the Review is a must-read for anyone interested in the world of energy. (Annual disclosure: I led the production of the Review for a dozen years…)
Paris barred most cars from the majestic road that goes past the Louvre Museum, then months later announced it would keep it that way. New York followed suit, making permanent a program that clears space on public roads for walking, biking and, in the case of 34th Avenue in Queens, Mexican folk dance classes.
In San Francisco, officials are weighing whether to keep part of John F. Kennedy Drive in Golden Gate Park closed to cars, prompting a tussle among drivers, pedestrians, bicyclists and a fine arts museum that lost easy public access to its facilities.
Leaders in other cities are pushing to do the same, seeing an opportunity to cement progress in making streets safer, more enjoyable and less polluting. The moves have also roiled long-running debates about the role of the automobile and the purpose of public streets.
In Washington, the D.C. Council in June appealed to the National Park Service to keep cars off a scenic stretch of Beach Drive in Rock Creek Park, a move also supported by Mayor Muriel E. Bowser (D). But one initial supporter of the idea, Del. Eleanor Holmes Norton (D-D.C.), tapped the brakes after opposition emerged, showing the complexities of limiting car travel, even in a city where local and federal officials have sought to emphasize other modes of transportation.
Carbon dioxide emissions in Los Angeles and the Washington DC/Baltimore regions fell roughly 33 percent in April of 2020 compared with previous years, as roads emptied and economic activity slowed due to the COVID-19 pandemic, according to a new study. But while the emissions reductions are significant, the method that scientists used to measure them may have the greater long-term impact…
In addition, a second study indicated that U.S. cities often underestimate their emissions when using bottom-up methods alone. A third study showed that combining bottom-up with top-down methods increases accuracy.
As more and more people around the world are getting vaccinated, one can almost hear the collective sigh of relief. But the next pandemic threat is likely already making its way through the population right now.
My research as an infectious disease epidemiologist has found that there is a simple strategy to mitigate emerging outbreaks: proactive, real-time surveillance in settings where animal-to-human disease spillover is most likely to occur.
In other words, don’t wait for sick people to show up at a hospital. Instead, monitor populations where disease spillover actually happens.
The current pandemic prevention strategy
Global health professionals have long known that pandemics fueled by zoonotic disease spillover, or animal-to-human disease transmission, were a problem. In 1947, the World Health Organization established a global network of hospitals to detect pandemic threats through a process called syndromic surveillance. The process relies on standardized symptom checklists to look for signals of emerging or reemerging diseases of pandemic potential among patient populations with symptoms that can’t be easily diagnosed.
There’s only one hitch: By the time someone sick shows up at a hospital, an outbreak has already occurred. In the case of SARS-CoV-2, the virus that causes COVID-19, it was likely widespread long before it was detected. This time, the clinical strategy alone failed us.
Zoonotic disease spillover is not one and done
A more proactive approach is currently gaining prominence in the world of pandemic prevention: viral evolutionary theory. This theory suggests that animal viruses become dangerous human viruses incrementally over time through frequent zoonotic spillover.
It’s not a one-time deal: An “intermediary” animal such as a civet cat, pangolin or pig may be required to mutate the virus so it can make initial jumps to people. But the final host that allows a variant to become fully adapted to humans may be humans themselves.
Viral evolutionary theory is playing out in real time with the rapid development of COVID-19 variants. In fact, an international team of scientists have proposed that undetected human-to-human transmission after an animal-to-human jump is the likely origin of SARS-CoV-2.
When novel zoonotic viral disease outbreaks like Ebola first came to the world’s attention in the 1970s, research on the extent of disease transmission relied on antibody assays, blood tests to identify people who have already been infected. Antibody surveillance, also called serosurveys, test blood samples from target populations to identify how many people have been infected. Serosurveys help determine whether diseases like Ebola are circulating undetected.
Turns out they were: Ebola antibodies were found in more than 5% of people tested in Liberia in 1982, decades before the West African epidemic in 2014. These results support viral evolutionary theory: It takes time – sometimes a lot of time – to make an animal virus dangerous and transmissible between humans.
What this also means is that scientists have a chance to intervene.
Measuring zoonotic disease spillover
One way to take advantage of the lead time for animal viruses to fully adapt to humans is long-term, repeated surveillance. Setting up a pandemic threats warning system with this strategy in mind could help detect pre-pandemic viruses before they become harmful to humans. And the best place to start is directly at the source.
My team worked with virologist Shi Zhengli of the Wuhan Institute of Virology to develop a human antibody assay to test for a very distant cousin of SARS-CoV-2 found in bats. We established proof of zoonotic spillover in a small 2015 serosurvey in Yunnan, China: 3% of study participants living near bats carrying this SARS-like coronavirus tested antibody positive. But there was one unexpected result: None of the previously infected study participants reported any harmful health effects. Earlier spillovers of SARS coronaviruses – like the first SARS epidemic in 2003 and Middle Eastern Respiratory Syndrome (MERS) in 2012 – had caused high levels of illness and death. This one did no such thing.
Fewer than 1% of participants in this study tested antibody positive, meaning they had been previously infected with the SARS-like coronavirus. Again, none of them reported negative health effects. But syndromic surveillance – the same strategy used by sentinel hospitals – revealed something even more unexpected: An additional 5% of community participants reported symptoms consistent with SARS in the past year.
This study did more than just provide the biological evidence needed to establish proof of concept to measure zoonotic spillover. The pandemic threats warning system also picked up a signal for a SARS-like infection that couldn’t yet be detected through blood tests. It may even have detected early variants of SARS-CoV-2.
Had surveillance protocols been in place, these results would have triggered a search for community members who may have been part of an undetected outbreak. But without an established plan, the signal was missed.
From prediction to surveillance to genetic sequencing
The lion’s share of pandemic prevention funding and effort over the past two decades has focused on discovering wildlife pathogens, and predicting pandemics before animal viruses can infect humans. But this approach has not predicted any major zoonotic disease outbreaks – including H1N1 influenza in 2009, MERS in 2012, the West African Ebola epidemic in 2014 or the current COVID-19 pandemic.
Predictive modeling has, however, provided robust heat maps of the global “hot spots” where zoonotic spillover is most likely to occur.
Long-term, regular surveillance at these “hot spots” could detect spillover signals, as well as any changes that occur over time. These could include an uptick in antibody-positive individuals, increased levels of illness and demographic changes among infected people. As with any proactive disease surveillance, if a signal is detected, an outbreak investigation would follow. People identified with symptoms that can’t be easily diagnosed can then be screened using genetic sequencing to characterize and identify new viruses.
This is exactly what Greg Gray and his team from Duke University did in their search for undiscovered coronaviruses in rural Sarawak, Malaysia, a known “hot spot” for zoonotic spillover. Eight of 301 specimens collected from pneumonia patients hospitalized in 2017-2018 were found to have a canine coronavirus never before seen in humans. Complete viral genome sequencing not only suggested that it had recently jumped from an animal host – it also harbored the same mutation that made both SARS and SARS-CoV-2 so deadly.
Let’s not miss the next pandemic warning signal
The good news is that surveillance infrastructure in global “hot spots” already exists. The Connecting Organisations for Regional Disease Surveillance program links six regional disease surveillance networks in 28 countries. They pioneered “participant surveillance,” partnering with communities at high risk for both initial zoonotic spillover and the gravest health outcomes to contribute to prevention efforts.
For example, Cambodia, a country at risk of pandemic avian influenza spillover, established a free national hotline for community members to report animal illnesses directly to the Ministry of Health in real time. Boots-on-the-ground approaches like these are key to a timely and coordinated public health response to stop outbreaks before they become pandemics.
It is easy to miss warning signals when global and local priorities are tentative. The same mistake need not happen again.
Researchers are calling for a ‘paradigm shift’ in combating airborne pathogens such as COVID-19, demanding universal recognition that infections can be prevented by improving indoor ventilation systems.
Transitioning from being a postdoctoral researcher to a laboratory leader comes with a suite of challenges. Not only do new principal investigators often have to relocate to a new city or country, but they also have to acquire funding, recruit lab members, teach, launch research programmes, develop outreach initiatives and complete administrative duties. These pressures have been amplified by the pandemic. Five new principal investigators share their experiences and advice for other rookie lab leaders.
Undergraduates often find research opportunities through university labs and government programmes. The experience can boost their confidence and develop their interest in pursuing careers in science, technology, engineering and mathematics. But when the COVID-19 pandemic started, many of these programmes were cancelled, and others restricted the number of participants.
Students adapted by seeking out opportunities through university alumni networks or conducting scientific projects at home. Nature asked five undergraduates about their experiences of doing research as competition for places increased during the pandemic, and about their advice for other early-career scientists.