The study was carried out by a team of researchers from the Department of Epidemiology of the National Institute of Health Doutor Ricardo Jorge (INSA) and aimed to evaluate the contribution of different demographic groups to the transmission of covid-19, as well as their epidemiological characteristics, including susceptibility to infection and transmission capacity.

Researchers have developed mathematical modelling methods to study the transmission dynamics of the SARS-CoV-2 virus during the first phase of the epidemic in Portugal in early 2020.

In the work carried out by INSA, the Portuguese population was stratified by age group, with the epidemiological characteristics of each group taken into account, as well as the pattern of contacts between the groups.

“The results obtained demonstrated that the age group that contributed most to the transmission of SARS-CoV-2 during the initial phase of the epidemic in Portugal (March 2020) were individuals between 30 and 39 years old, and it is also worth highlighting that individuals between 30 and 59 years old had a relative contribution of more than 60%”, highlights INSA.

The researchers say these groups were not necessarily the most affected by the disease, as the age group most affected was those aged 70 and over.

However, the contribution of those over 70 years of age to transmission was considerably lower than that of people between 30 and 39 years of age.

“These results demonstrated that prioritising measures in the groups most affected by the disease could reduce the impact on health services, but it is not necessarily the best strategy to reduce the transmission of the infection,” state the authors of the study published on the INSA website.

The study also developed a mathematical tool that allows the rapid assessment and projection of the impact of a public health intervention.

“The results obtained allow a better understanding of the groups to be prioritised for public health interventions in the context of an outbreak of a disease with characteristics similar to COVID-19 in the Portuguese population,” they highlight.

The work also had the support of the Research Support Foundation.