In a modeling study, an estimated 1.7 billion people are at an increased risk of the virus, but a much smaller percentage would require hospitalization.
In a new modeling study, investigators observed that approximately 22% of the world’s population has at least 1 underlying health condition, putting 1.7 billion people at risk for coronavirus 2019 (COVID-19).
Andrew Clark, PhD, associate professor, Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, led an international team looking at the world’s population in creating modeling to understand better the continuing global risk of COVID-19.
Their findings were reported in The Lancet Global Health.
The modeling study involved 188 countries, and those with the greatest risks included African countries with a high HIV/AIDS prevalence, island nations with high diabetes prevalence, and countries with an aging population.
As the entire world begins to come out of the quarantine, understanding of which portions of the population will be affected is important to understand.
“As countries move out of lockdown, governments are looking for ways to protect the most vulnerable from a virus that is still circulating,” Clark said in a statement. “We hope our estimates will provide useful starting points for designing measures to protect those at increased risk of severe disease.”
Such starting points, Clark noted, may involve social distancing measures more appropriate to such a person’s risk, or prioritizing at-risk persons for future vaccinations.
However, investigators also noted not all the individuals with existing health conditions would develop a severe case of COVID-19. They estimate 4% (349 million) of the world’s population would need to be hospitalized. They added that the increased risk of severe COVID-19 could be quite modest for many with underlying conditions.
The investigators looked at disease prevalence data from the Global Burden of Diseases, Injuries and Risk Factors Study (GBD) 2017, the United Nations population estimates for 2020, and the list of underlying health conditions relevant to COVID-19, as defined by current guidelines. These risk factors included cardiovascular disease, chronic kidney disease, diabetes, and chronic respiratory disease.
To help determine the degree of increased risk, the investigators also provided separate estimates of the proportion of all people (with and without underlying conditions) who would require hospitalization if infected. They calculated those at high risk using infection hospitalization ratios for COVID-19 and made adjustments for differences between countries.
Whereas countries with older populations have more people with at least 1 condition, countries who have younger populations had less people with at least 1 underlying condition. Less than 5% of people under 20 years old, but more than 66% of those aged 70 and above, have at least 1 underlying condition.
The investigators looked at underlying chronic conditions only in the guidelines and did not look at other potential risk factors such as ethnicity and socioeconomic deprivation. They also pointed out this should be used as a starting point for policy makers.
In a comment accompanying the findings, Nina Schwalbe, MPH, professor at the Columbia University Mail School of Public Health, echoed Clark and colleagues in calling for an evolution from the “one-size-fits-all approach to one that centers on those most at risk.”
“This will need to happen at both the individual and community level,” Schwalbe, who was not involved with the study, wrote. “Considering the relevance of social determinants, such an approach requires urgently improving communication about COVID-19; increasing access to health services, including palliative care, for those already socially vulnerable; and providing economic support to cope with the mitigation.”