Introduction by Croakey: “Science is sterile if it lacks a social purpose,” according to a leading epidemiologist and public health expert, speaking at the World Congress of Epidemiology (WCE) 2021 last week.
In his keynote speech to the Congress, Professor K Srinath Reddy from the Public Health Foundation of India, called for greater COVID vaccine equity and highlighted the importance of science’s social mission.
This set the tone for the key themes of social equity, environmental impact and mental health explored in other presentations at the wide-ranging WCE, held virtually from Melbourne on 3-6 September.
Nicole MacKee reports for the Croakey Conference News Service below.
Nicole MacKee writes:
“Global solidarity” is more important than ever, according to a leading epidemiologist who is calling on wealthy nations to help to ensure that low-income countries have equitable access to COVID-19 vaccines.
Speaking to Croakey after the World Congress of Epidemiology, Professor K Srinath Reddy raised concerns about plans to roll out COVID vaccine booster programs in high-income countries, while initial vaccination programs in low-income countries were lagging.
“This is not just a moral issue,” he said, “It’s also a scientific one.”
Only 20 percent of people in low- and middle-income countries have received a first dose of COVID vaccine, compared with 80 percent of people in high- and middle-income countries.
The World Health Organization Director-General, Dr Tedros Adhanom Ghebreyesus, recently reiterated calls for a moratorium on wealthy countries rolling out COVID vaccine booster programs until 2022, while COVAX announced that its goal of delivering two billion vaccine doses in 2021 has had to be delayed to the first quarter of next year.
Reddy said lower vaccination rates in poorer nations were likely to lead to the emergence of dangerous variants with spike proteins that may not respond to our current vaccines.
“If higher income countries continue to believe they live in a bubble from the rest of the world, they will find that these variants will slip through the cracks,” he told Croakey.
“Unless you treat the whole of humanity as a single host, and enhance collective immunity, you won’t be able to deal with this virus.”
Reddy’s call for vaccine equity aligned with themes in his keynote address to the WCE.
“Science has a social mission,” Reddy told WCE participants, “Science is sterile if it lacks a social purpose and … public policy will crumble on clay feet if it does not stand on the strong of base of sound science.”
Reddy said epidemiology had gained strength as a scientific discipline and had excelled in identifying cause and effect in health, from the genomic to the social and environmental levels.
The next challenge, Reddy said, was to adapt to complexity thinking and to ensure knowledge was applied for social benefit.
“Ultimately, society must benefit from what we do in the way of knowledge creation and knowledge translation,” he said, emphasising the importance of advancing equity and of interdisciplinary research.
Catching up to COVID
Reddy said epidemiology had led the way in many areas of the public health response to COVID, but in some domains, the field had been playing “catch-up”.
“I was trained to have a strong belief in the rigid hierarchy of research, with clinical trials the gold standard, and ecological studies at the lowest rank,” Reddy told Croakey.
But in the age of COVID, ecological studies have proven to be critical in generating hypotheses, including in the role of mask-wearing in addressing COVID transmission.
“Different research designs have different strengths and evidence from them is complementary and cumulatively contributes to decision making in complex systems,” Reddy said.
“When there were calls to advocate for mask-wearing, purist researchers asked, ‘but where are the trials?’”
Reddy noted that it was actually a historian who dug through the archives to discover a 60-year-old error in the definition of a 5-micron boundary for aerosol transmission.
He said WHO didn’t recommend the wearing of masks to prevent COVID transmission until 30 April 2021 – more than a year after the start of the pandemic – with the US Centers for Disease Control and Prevention following suit in May 2021.
“While a clinical trial is still best in testing a new drug or vaccine, when it comes to the complex interactions in daily life, we have to take a different approach.”
Reddy called for universities to train epidemiologists to become “change makers” and to focus on developing “T-shaped” researchers.
“[These are] individuals who have domain expertise in depth in one or two areas, but they also have trans-disciplinary thinking and real-world awareness that allows them to partner productively with people from other allied disciplines in order to carve solutions that advance world science and public health.”
Professor Cesar Victora, Emeritus Professor at the Federal University of Pelotas, was presented with the 2021 Richard Doll Oration Prize at the Congress’ conclusion on Monday 6 September.
In his acceptance oration, Victora encouraged early career epidemiologists to embark on three types of research: academic (to advance knowledge); advocacy (to promote change); and operational (to plan, evaluate and improve programs).
He also reflected on how, in his recent EPICOVID19 project, all three research types could overlap.
“Brazil was very badly hit by COVID,” Victora said, “There was gross under-reporting with only about one in seven cases being reported.”
Victora and his research team conducted large-scale epidemiological studies, and a surprise early finding was that all six cities with the highest COVID prevalence in the first wave of COVID in May 2020 were along the Amazon River.
The team also tracked COVID prevalence by ethnicity and found that the prevalence among the Indigenous population was about five times that of the White population. People with mixed ancestry also had about twice the COVID prevalence of the White population.
Victora said this aspect enabled the study to have an advocacy point of view, and its equity-focussed evaluation of missed childhood vaccination rates during the pandemic also provided an operational angle to the work.
“People were afraid to take their kids to health facilities because of COVID and we had about 20 percent of kids in Brazil miss vaccinations during their first year of life,” he said. “This ranged from 22 percent in the poorest to 15 percent in the wealthiest [populations], following a steady social gradient.”
“This is a fine example of how a study can have an academic component (showing the spread of COVID along the Amazon River), as well as an advocacy component by looking at the ethnic differences, and also helping improve health programs with operational evaluation research (for example, the missed immunisations among children).”
Countdown to 2030
The WCE also heard presentations from an array of international researchers focussing on efforts to meet the United Nation’s 2030 deadline for its Sustainable Development Goals (SDG).
Introducing the first of three sessions on the Countdown to 2030, Victora said the initiative was launched in 2005 to monitor the Millennium Development Goals, later shifting to track the Sustainable Development Goals (SDG). The program’s emphasis is on monitoring progress on reproductive, maternal, newborn and child health.
Franciele Hellwig of the International Center for Equity in Health in Brazil presented research on the inequalities in modern contraception, and the role of sterilisation in contraception, in low- and middle-income countries.
“Coercive sterilisation has been documented, especially among the poorest women who are dependent on public policies and government support to access contraception,” she said, noting that SDG 5 included a target to ensure universal access to sexual and reproductive health and reproductive rights.
The researchers surveyed women aged 15-49 from 105 low- and middle-income countries and found that appropriate access to modern contraceptive methods ranged from six percent in Albania to 94 percent in Brazil. The rate of sterilisation was higher than 25 percent of women in more than 20 countries, ranging from 25 percent in Papua New Guinea to 76 percent in India.
A variable pattern of wealth inequality was found, reflecting cultural norms, public policies, financial schemes, and education levels.
Hellwig called for increased access to a wide range or reversible contraceptives and to counselling on the advantages and disadvantages of the various contraceptive options.
Women’s empowerment key to childhood vaccination rates
A focus on women’s empowerment could help to drive up children’s vaccination rates, according to Bianca O Cata-Preta, also from the International Center for Equity in Health.
Cata-Preta said the world had made huge progress in childhood immunisation, but since 2010, the global coverage of basic vaccines (such as diptheria-tetanus-pertussis (DTP), polio and measles vaccines), remained at about 85 percent, below the WHO’s target of 90 percent coverage.
Thirteen million children went without vaccination every year, Cata-Preta said, and the WHO had set a target of 50 percent reduction in the number of unvaccinated children by 2030.
Cata-Preta said addressing the social determinants of vaccination, including women’s empowerment, would be critical to meeting this target.
“The literature has shown that more educated women, with higher knowledge of all the vaccines and decision autonomy, are more likely to take their children to health services to receive vaccines,” Cata-Preta told the WCE.
Cata-Preta and colleagues analysed vaccination rates (tracking children aged 12-23 months who’d had no doses of DTP vaccine) and assessed women’s empowerment using the SWPER (Survey-based Women’s emPowERment index) in 50 mostly low-income countries. Of more than 94,000 children surveyed, 9.2 percent had not received a DTP vaccination.
They found the children of women with low empowerment were more than three times less likely to have been vaccinated than the children of women with high empowerment. They also found that the higher the national prevalence of children not receiving DTP vaccine, the higher the inequality.
Heatwaves of greater intensity, frequency and duration will soon be a reality in Australia as climate change takes hold, said Dr Blesson Varghese of the University of Adelaide, who has investigated the impact of heatwaves on Adelaide’s GP services and emergency departments.
Several factors affected people’s vulnerability to heatwaves, he said, from exposure factors such as age of housing and building density to sensitivity factors such as elderly age, living alone and unemployment.
Over a five-year period, Varghese’s study found that GP visits in the city increased by 15 percent during severe and extreme heatwaves, compared with non-heatwaves, while emergency department presentations rose by nine percent during heatwaves.
Varghese found that heatwave morbidity varied across Adelaide. Areas with greater heatwave impacts were characterised by social isolation, multi-level housing, no vehicle access, and areas with low vegetations. Areas with populations with higher rates of hypertension and overweight also fared worse during heatwaves.
“This suggests that a one-size fits all approach is not suitable to reduce the health impacts of heatwaves and highlights the need to consider the specific context of an area when designing prevention and adaptation strategies.”
Varghese said the research was informing a Bureau of Meteorology shift from hazard-based warning to an impact-based system, changing its messaging from ‘what the weather will be like’, to ‘what the weather will do to you’. This will enable targeted warnings and strategies to reduce the health burden among those most vulnerable to heatwaves.
Green space benefits
Greater access to green space in urban environments may help to ward off loneliness and its health impacts, according to research presented by Professor Thomas Astell-Burt of the University of Wollongong.
More than one in four Australians reported feeling lonely at least a few times a week, Astell-Burt said, adding that loneliness was a risk factor for inflammation, depression, self-harm, suicide attempts, heart disease, neurodegeneration and premature death.
“Loneliness should be a public health priority to address, and often isn’t,” Astell-Burt said.
“Green spaces help to bring communities together as a focal point for connection, they help to foster senses of belonging, not only to the communities in which we live but also connections to [natural] surroundings. All has this has been shown to keep us mentally healthy, as well as preventing a range of chronic conditions.”
While there was scant research in this area, Astell-Burt said his research group’s longitudinal study, which was published in the International Journal of Epidemiology in April 2021, tracked more than 6,500 people who did not feel lonely at baseline. After four years, 12 percent of study participants reported feeling lonely.
The researchers found that people living in areas with access to at least 30 percent green space had about 25 percent lower odds of becoming lonely. And the impact was even greater for those living alone, who had a 50 percent lower risk of loneliness if they had ready access to green space.
Housing policies that support the security of people living in private rental accommodation may help reduce mental health impacts, Dr Ang Li of the University of Melbourne’s School of Population and Global Health told the WCE.
She said private rental housing was once considered a transitional step to towards home ownership, but an increasing number of people were spending more time in the private rental market.
“During the last two decades, the proportion of households renting from private landlords has increased by six percent, while home ownership has fallen by four percent,” Li said.
She said residents in private rental accommodation moved more often than homeowners and social housing tenants, and weak legislation in Australia further compounded their vulnerability”.
Housing instability disrupted social networks, employment, and access to health care, and could lead to stress, anxiety and poor mental health, Li said.
But, she said, accommodation stability – whether that be through home ownership or private rental security – could be protective of mental wellbeing.
“The mental health of private renters had a larger improvement, compared to homeowners, as the number of years in their current dwelling increased,” Li said.
The results suggested that although home ownership was associated with better mental health, stable and secure rental tenancy can protect the mental wellbeing for renters, Li said. “Housing systems that provide protection and support for tenure security for tenants are beneficial for their mental health.”
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