There is serious concern about how SARS-CoV-2 will overlap with other common respiratory pathogens in the winter months. We cannot rule out a perfect storm situation in which the coronavirus coincides with other viruses that cause flu, bronchiolitis and pneumonia, responsible for hospitalizations and deaths in the most vulnerable sectors of the population.
It has been suggested that the risk of death in people infected with influenza and SARS-CoV-2 simultaneously is higher than in those who were only infected by the coronavirus. Especially in people over 70 years old.
We do not know what will happen, but we can look at what has happened in the southern hemisphere during June, July and August of this year, the months that constitute the flu season in that part of the planet.
The data is pretty compelling: influenza and other respiratory viral infections have practically disappeared from the southern hemisphere.
Let’s look at the data on admissions to pediatric intensive care units in several Latin American countries, of children with respiratory problems due to influenza or respiratory syncytial virus infections. These show that, during the COVID-19 pandemic, admissions to ICUs due to these viruses have been reduced by between 78% and 92%.
Australia has also reported a reduction of more than 98% in the detection of influenza and other respiratory viruses in children, despite having kept schools open. Also in New Zealand the flu has disappeared: it has been reduced by more than 99%.
The same has happened in Chile: unlike in previous years, only the SARS-CoV-2 coronavirus has been detected during the winter of 2020.
Other causes, such as a decrease in diagnostic ability or interference between the two viruses, cannot be ruled out. However, it is very likely that the confinement measures, the use of masks, hygiene and social distance, as well as the reduction in travel and a more intense influenza vaccination campaign have contributed to mitigating the circulation of the influenza virus and reducing its impact. Nor do we know why these measures have been able to affect other viruses and, on the contrary, SARS-CoV-2 continues to increase. Could it be due to a larger role for supercontagators in coronavirus epidemiology?
We do not know how the flu will behave this winter in the northern hemisphere, but these data are cause for hope and encourage the continuation of containment measures. Perhaps in the future some of these measures will have to be added to reduce the impact of influenza on the most vulnerable populations, in addition to vaccination, the only preventive tool we have so far.
Ignacio López-Goñi, Professor of Microbiology, University of Navarra
This article was originally published on The Conversation. Read the original.
