Confronting the Dangers of Silent Spread Is Necessary to Prevent Future Pandemics

Addressing the risks of silent spread is necessary to prevent future pandemics

Who Joshua S. Weitz

The typical runny nose of a common cold or the fever and pain associated with the flu mark the way respiratory diseases are classified, with their symptoms. Public health messages focus on these symptoms, asking those who are symptomatic to stay home and avoid others. That makes sense. It reduces the risk of one case becoming many.

But what if transmission is not necessarily associated with symptoms? COVID has proven that diseases can lead to it catastrophic damage to society when they spread without symptoms. Therefore, preventing future pandemics requires greater investment in targeted public health interventions to reduce transmission, including from infected people who feel well.

In fact, asymptomatic transmission was essential for the transition of COVID from a rapid outbreak in Wuhan, China in early 2020 to a global pandemic that caused more than one million deaths in the US by May 2022. People who felt well transmitted their infection to others before developing symptoms (in a presymptomatic phase) or even if they never developed symptoms. comparisons of initial occurrence data they revealed that approximately half of the infected people were asymptomatic. That would be good news if asymptomatic infections were not transmissible. But it wasn’t like that.

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On February 23, 2020, researchers from China, France and the US released a joint analysis More than 450 cases of COVID transmission in 93 cities in China. The study focused on the serial interval: the time between when someone shows symptoms and when someone who infects them shows symptoms. Contrary to expectations, the analysis showed that serial intervals for COVID were often less than zero, meaning that individuals showed symptoms before the person who infected them. These statistics were evidence of extensive presymptomatic transmission. Public health experts tried to raise the alarm Efforts to stop transmission through symptom screening (such as high temperature or short-breathing tests) were bound to fail and “unprecedented measures” were needed to combat it.

The deadly effects of asymptomatic transmission soon reached the U.S. On March 10, 2020, the Skagit Valley Chorale gathered outside of Seattle for a rehearsal. Despite efforts to limit physical contact, after a few days it became apparent that someone in the group had inadvertently infected others. In the end, 53 of the 61 attendees were infected, and two died. This superexpansion event It revealed that COVID could spread in the air in the absence of symptoms. However, the importance of asymptomatic transmission remained controversial. June 8, 2020 A senior WHO official stated asymptomatic transmission was “very rare”. The pandemic was raging, but we were losing precious time to combat its silent spread. The consequences were serious. As head of the White House’s coronavirus task force, Anthony Fauci He stated in August 2020: “I’ve never seen a viral disease where you have multiple symptoms, no symptoms at all, 40-45 percent of the time, that’s serious enough to kill you.” Asymptomatic transmission represents a double-edged sword. Individual outcomes may be better, but silent spread leads to more infections that can lead to worse population outcomes.

What can be done to reduce asymptomatic transmission? Early responses to the pandemic included limits on gatherings and stay-at-home orders. But the unusual mix of severe and symptomatic outcomes of COVID catalyzed a diverse group of stakeholders to invest in unconventional approaches to reduce the risk of its silent spread. These approaches include risk assessment in real time, large-scale rapid testing, context-specific masking and improve indoor air quality. Each of these has a complementary role to play in reducing silent spread, and if implemented at scale, can be an essential weapon in the ongoing battle against pathogens of pandemic potential.

In the absence of symptoms, risk assessment in real time driven by occurrence patterns and extended through mobile accessible dashboards can function as a threat prediction. These dashboards can provide mapped information on infectious disease risks, among other things Reported outbreaks of COVID in wastewater. People could then choose to avoid events that exceeded their risk tolerance. However, even if someone attends an event, rapid on-site testing and the use of masks can limit infections. This can be a tremendous force for good, especially nursing homes and long-term care facilitiesWhich accounted for a disproportionate share of the overall deaths from COVID. Regardless of individual actions, infrastructure investments in indoor air quality (through improved filtration, air turnover rates and UV-C sterilization of upper rooms) can improve health outcomes.

Finally, we must commit significant resources to developing and effectively deploying vaccines both in the United States and globally, especially in developing countries. A year after the emergence of COVID, the production of millions of vaccine doses represents an incredible validation of power. basic research and public-private collaboration. However, the production of vaccines does not always lead to shots in the arm. It is required by public health agencies improve messaging both to explain why individuals can benefit from vaccines, when they should get vaccines (and boosters) and what each vaccine is supposed to do. In the case of COVID, mRNA vaccines were shown reducing rates of symptomatic disease by more than 90 percent. However, these vaccines do not prevent all infections. This means that vaccinated people can still get infected, test positive and infect others, but the risk of serious outcomes is reduced. This is exactly the point. But the failure of vaccines to provide perfect protection against infection (symptomatic or otherwise) has accelerated it. massive spread of misinformation this threatens to reduce vaccination uptake, not just for flu and COVID, but also for preventable childhood diseases, including measles.

It’s been almost five years since the early warning of the new coronavirus spreading in Wuhan was fueled by asymptomatic transmission that would soon lead to a global pandemic. At the time, the threat to public health and socio-economic stability seemed remote. Since then scientists, public health experts, government agencies and the biotech sector have developed a set of countermeasures to address the dangers of silent spread; however, there is more to be done, among other things. in the silent spread of bird flu in wild and domestic animals. Converting this momentum into data-driven threat assessments, high-impact interventions (including testing and air quality improvements), faster vaccine deployments, and more effective messaging from physicians and public health agencies is essential to reducing the ongoing burden of COVID; these actions will better prepare the world to identify, prevent, and respond to future pandemic threats before it is too late.

This is an opinion and analysis article, and the views expressed by the author(s) are not necessarily their own. American scientific