Opinion – Pedro Hallal: A pandemic is a disease of the population

In 1985, English epidemiologist Geoffrey Rose wrote a historical article entitled “Sick individuals, sick populations” (in Portuguese, “Sick individuals, sick populations”). In the text, the author explains the differences between an individual approach, to treat a disease that affects individuals, and a population-based approach, to treat a disease that affects the population.

To understand the concept in a simple way, we can use the example of a common disease: high blood pressure.

In an individual approach, the patient with high blood pressure will receive medication to control blood pressure, receive counseling on healthy habits, and the objective is for the patient to maintain their blood pressure levels at normal values. However, when the disease exceeds individual limits and reaches some degree of lack of control, a population-based approach is necessary. In this case, one can mention legislation to control sodium levels in foods, creation of cycle paths to encourage the population to practice physical activity, among other measures that help to control the pressure levels of the population, and not just one individual. The combination of an individual approach and a population approach will ensure the best public health outcome.

Since the Covid-19 pandemic began, there is an inability of some managers (Brazil is an example) to understand that the pandemic is a disease that affects the population and, therefore, will not be defeated with an individual approach. The entire logic of ominous early treatment, for example, is based on the idea of ​​treating one patient at a time, rather than using population-based approaches to reduce the circulation of the virus.

Likewise, the president’s and the minister of health’s distorted view of vaccination mixes denial with a misperception that Covid-19 is a disease of individuals, not the population. If Covid-19 were a disease of individuals, there would be no problem in encouraging “whoever wants to get vaccinated”. But as Covid-19 is a disease that affects the population, not vaccinating one hinders the other. In other words, the unvaccinated does not only harm him, but the entire control of the pandemic.

When we look at the worldwide data on Covid-19, we see that we are a long way from winning the Covid-19 pandemic globally. The average daily death toll peaked at 1.8 deaths per 1 million people in February 2021, but will still turn the year around 1 death per 1 million people a day. With the arrival of the omicron variant, it is possible that the downward trend will be reversed.

To win the Covid-19 pandemic, we need to treat it for what it is: a disease that affects the population. In this case, the world population. And to treat a disease that affects the population, we need a combination of strategies to be adopted internationally:

1. Accelerating immunization with equity: While we need to accelerate immunization, we need to ensure that it takes place in a minimally uniform manner across countries.
2. Adoption of large-scale genomic surveillance: for early identification of new variants, allowing existing vaccines to be adapted quickly when needed.
3. Fighting denial theories and actions: to control the pandemic, it is necessary that denial, anti-science, anti-vaccine theories and actions are fought and ignored in decision-making on policies to fight the pandemic.