How prepared are we for another pandemic? Mathematical insights pinpoint lessons on airborne viral transmission
Half a decade on from the start of the COVID-19 pandemic, a study by the University of Surrey highlights the significant impact of combined public health measures in reducing airborne viral transmission. High-quality face masks were shown to reduce transmission risk by ninefold, while doubling indoor air ventilation cut the risk by nearly a third, providing valuable insights to support future prevention strategies for respiratory diseases.
In 2020, the world came to a near standstill as rising COVID-19 cases prompted unprecedented lockdowns, travel restrictions and widespread public health measures. The World Health Organization estimates that more than three million deaths were directly attributed to the virus during the first year of the outbreak, underscoring the devastating toll of the pandemic on global health and economies.
To better understand the dynamics of airborne transmission and inform future preparations, Dr Richard Sear, Associate Professor at Surrey’s School of Mathematics and Physics, explored how the virus spreads during contact and the role of protective measures in reducing risk.
Dr Sear said:
“I’ve tried to measure how effective strategies, such as mask-wearing, are for the transmission of airborne viruses. This is both for any future pandemic, and for seasonal flu. I combined modelling with data from the UK’s NHS COVID-19 app. While these estimates are highly approximate, they provide guidance on the value of measures such as face masks, social distancing and improved indoor air quality, which could be tested in the future.”
Factors such as viral load, ventilation and individual susceptibility are likely to influence a significant variability in COVID-19 transmission rates, with some contacts posing a much higher risk than others. These findings highlight the importance of addressing environmental and behavioural factors in public health strategies.
In terms of personal protective equipment (PPE), high-quality face masks, such as N95/FFP2, were found to be particularly effective in reducing transmission risk, decreasing the effective reproduction number for COVID-19 transmission by a factor of approximately nine when worn by the entire UK population. Even individual use of N95 masks can lower transmission risk by threefold, no matter the duration of contact, whereas surgical and cloth masks are much less effective.
Ventilation also plays a critical role in controlling airborne transmission, as viral particles linger in poorly ventilated spaces, compounded by individual behaviours, such as close-contact interactions, speaking or coughing. By doubling the air turnover rate indoors, whether that’s through open windows and doors or increasing speed on air conditioning systems, transmission can be reduced by as much as 30%. Complementing good ventilation with physical distancing further minimises the risk.
Dr Sear added:
“The COVID-19 pandemic was terrible for many of us, which is why it’s important that we learn from our experiences. It also demonstrated how quickly we can develop and roll out vaccines when faced with a global health crisis. Moving forward, both we as individuals and our leaders have an opportunity to apply these lessons to better control respiratory diseases - not only to head off any future pandemics, but to also manage seasonal diseases such as flu and RSV.”
[ENDS]
Notes to editors
Dr Richard Sear is available for interview, please contact mediarelations@surrey.ac.uk to arrange.
The full paper is available at https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.064302#s6
Journal
Physical Review E
Article Title
Estimating the population-level effects of nonpharmaceutical interventions when transmission rates of COVID-19 vary by orders of magnitude from one contact to another
Access to vaccines and clinical trials for pregnant women vital in pandemics
Murdoch Childrens Research Institute
The vast majority of women who contract bird flu during pregnancy and their unborn baby will die from the virus, according to a new study. And the findings stress the importance of early inclusion of pregnant women in public health vaccination programs during pandemics.
The research, led by Murdoch Children’s Research Institute (MCRI), recommends that as human cases of avian influenza viruses A (H5N1 and H5N2) increase, an awareness around the vulnerability of pregnant women to a new pandemic is urgently needed.
The systematic review of more than 1500 research papers examined 30 reported cases of bird flu in women who were pregnant across four countries.
Published in Emerging Infectious Diseases, the review found that women died in 90 per cent of cases when infected with bird flu during pregnancy with almost all their babies dying with them. Of the small number of babies who survived, 80 per cent were born prematurely.
MCRI Dr Rachael Purcell said the inclusion of pregnant women as early as possible in pandemic planning must be a key priority.
“Increasing numbers of human cases of avian influenza associated with outbreaks in birds and mammals raises concerns about the possibility of another pandemic in the near future,” she said.
“Despite being a high-risk population, pregnant women are often excluded from vaccine trials, priority access to therapeutics and delayed entry into public health vaccination programs. A paradigm shift is required to routinely include pregnant women in pandemic preparedness programs to avoid preventable deaths.
“This could be achieved through utilising the capacity of existing surveillance systems such as the Global Vaccine Data Network or the Vaccine Safety Datalink, the planning of vaccine trials to include the complex needs of pregnancy, and the upscaling of adverse reaction detection systems to identify risks in pregnant women.”
MCRI Professor Jim Buttery said during pandemics vulnerable populations were often at high risk of severe disease and death.
“Pregnant women have experienced high death and critical illness rates during the influenza and SARS-CoV-2 pandemics and the Ebola epidemic,” he said. Global efforts are needed to proactively recognise and mitigate this risk prior to the onset of a pandemic, rather than as a reactive process once a health crisis has started.
“Ethical pandemic preparedness to avoid preventable deaths requires early inclusion of vulnerable populations in vaccine development, monitoring and trials. A pregnancy focused research agenda should be developed and facilitated by medical review boards, regulators and policy makers.”
MCRI’s research team welcomed the Federal Government’s $95 million investment to help prepare against H5N1. Australia is the only continent that remains free of the deadliest bird flu strain.
Read about the bird flu situation in Australia, what to do if you travel overseas and the importance of getting an annual influenza vaccine.
Researchers from the University of Melbourne, The Royal Children’s Hospital, Monash Health and Monash University also contributed to the findings.
Publication: Purcell R, Giles ML, Crawford NW and Buttery J. ‘Systematic Review of Avian Influenza Virus Infection and Outcomes During Pregnancy,’ Emerging Infectious Diseases. DOI: 10.3201/eid3101.241343
*The content of this communication is the sole responsibility of MCRI and does not reflect the views of the NHMRC.
Available for interview:
Dr Rachael Purcell, MCRI Infectious Diseases researcher
Professor Jim Buttery, MCRI Group Leader, Epidemiology Informatics
Journal
Emerging Infectious Diseases
Method of Research
Systematic review
Subject of Research
People
Article Title
Systematic Review of Avian Influenza Virus Infection and Outcomes During Pregnancy
Cultural differences account for starkly different responses to COVID-19
Association for Psychological Science
Hello Kitty has eyes but no mouth. The unique anatomy of the world-famous Japanese cartoon girl, who appears to be a cat, reflects an important aspect of her nation’s cultural norms—she doesn’t need a mouth because in Japan, it is more important to read the feelings of others than to broadcast your own. This tendency likely contributed to the easy adoption of mask-wearing among Japanese people during the COVID-19 pandemic, especially when compared to Americans who are averse to covering the facial feature most used to express their unique thoughts and feelings.
This issue of Psychological Science in the Public Interest explores the cultural differences between the United States and East Asian countries that contributed to divergent COVID-19 outcomes. APS William James Fellow Hazel Markus of Stanford University and her team illustrate how cultural defaults—or common-sense ways of thinking and feeling in a particular culture—account for the starkly different responses to the COVID-19 pandemic.
A preference for social choice, a willingness to wait and adjust, and a calm attitude are some of the cultural factors that led to a more effective response to the virus in the East Asian countries of Japan, Taiwan, and South Korea. In the United States, by contrast, individuals leaned toward personal choice, an attitude of control, and a tendency to become angry or experience other high arousal emotions.
These different cultural responses likely contributed to massive variations in the number of COVID-related deaths in each country. By March 2023, 1.1 million people had died in the United States, 73,000 in Japan, 17,700 in Taiwan, and 34,100 in South Korea.
“While variation in the number of COVID-19 deaths indicates that some nations were indeed better equipped to respond to this particular crisis than others, we do not suggest that one set of cultural defaults is generally ‘better’ or ‘worse’ than another,” wrote the authors. “Both default profiles outlined here carry historically derived cultural wisdom and have been adaptive and useful across a wide range of situations in the past.”
Markus’s coauthors include APS Fellow Yukiko Uchida (Kyoto University) and APS Fellow Jeanne Tsai, Angela Yang, and Amrita Maitreyi of Stanford.
The team synthesized literature from mainstream media, reports, quotes from high-level public figures, and analyses from journalists, academics, and other commentators to demonstrate how cultural defaults were apparent in the public messaging of each country’s COVID response.
“We demonstrate why particular pandemic behaviors were rational and made sense in one cultural context but were much less so in another,” the authors wrote. “Our argument is that these cultural defaults, especially when considered together, could have forecast many of the striking differences in pandemic responses and outcomes between the U.S. and the East Asian countries that are the focus here.”
In the final section of the paper, Markus and colleagues address how policymakers can identify and consider cultural defaults when planning how to respond to urgent global crises such as climate change.
“The need to understand not only that culture matters but also how and why it matters to everyday lived experience is in the immediate public interest and more pressing now than ever,” Markus and colleagues wrote.
In a commentary published alongside the report, Sara Cody considered her own role as director of public health for the Santa Clara Public Health Department in California during the pandemic.
“Many of the challenges we faced as the pandemic wore on likely reflect the cultural defaults related to individualism and/or independence as described in the paper,” she wrote. “I also recognize that many of the actions that I took and the way we saw our work in our Emergency Operations center also reflect cultural defaults very particular to the U.S.”
A second commentary from Ichiro Kawachi, a professor of social epidemiology at Harvard University, describes the paper as an important step forward in our understanding of the public health response to pandemic. Kawachi points out that cultural defaults do not operate in a vacuum but are constantly reinforced and manipulated by vested interests.
“Instead of resigning ourselves to the inexorable power of cultural defaults in influencing public opinion and decision-making, preparing ourselves for future crises demands that we take purposeful action to expose the manipulation of public discourse by vested interests and to educate the polity to resist ingrained habits of thinking, feeling, and acting,” he wrote.
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References
Cody, S. (2024). COVID and cultural defaults: A public health officer’s perspective. Psychological Science in the Public Interest, 26(1).
Kawachi, I. (2024). Culture as a social determinant of health. Psychological Science in the Public Interest, 26(1).
Markus, H. R., Tsai, J. L., Uchida, Y., Yang, A. M., & Maitreyi, A. (2024). Cultural Defaults in the Time of COVID: Lessons for the Future. Psychological Science in the Public Interest, 25(2), 41-91. https://doi.org/10.1177/15291006241277810
Journal
Psychological Science in the Public Interest
Method of Research
Literature review
Subject of Research
People
Article Title
Cultural Defaults in the Time of COVID: Lessons for the Future
Article Publication Date
19-Dec-2024
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