UC Berkeley assistant professor of demography Ayesha Mahmud and her colleagues from other universities found that climate change may lessen the severity of viruses such as influenza and respiratory syncytial virus, or RSV, but may also cause cases to occur more often.
Mahmud and her fellow researchers — Rachel Baker, Caroline Wagner, Wenchang Yang, Virginia Pitzer, Cecile Viboud, Gabriel Vecchi, C. Jessica Metcalf and Bryan Grenfell — published a paper about their findings in the scientific journal Nature Communications on Dec. 4.
RSV is a virus that infects many young children and can cause respiratory infections, including bronchiolitis and pneumonia in infants. It has also been implicated in some people’s development of asthma later in life.
The team collected data on RSV hospitalizations from 300 counties in the United States and all 32 states in Mexico. They then combined the RSV data with climate data, which included numbers on precipitation, humidity and temperature, to investigate patterns and what drives the transmission of these viruses, as well as to predict future RSV cycles using signs of climate change.
“We found that the intensity of epidemics changed in the future,” Baker, the first author of the paper, said in an email. “For most of the US, epidemics are expected to become less intense in the future, but with more cases occurring throughout the year, for instance, in the summer months. However, for tropical locations, changes to epidemics really depended on changes to future rainfall.”
Baker added that, given different climate models, results can vary and that higher rainfall could lead to more severe and unpredictable outbreaks of RSV.
According to Baker, this finding is significant because not much similar research has been conducted before. While there has been work done on the relation between climate change and vector-borne diseases, such as malaria and dengue fever, there has been little research on diseases that transmit person-to-person.
“Changes to epidemic patterns can affect the age of infection, timing of future vaccinations (though there is no vaccine for RSV at the moment) and put pressure … (on) public health resources,” Baker said in the email. “Developing a better understanding of the potential effect of climate change on these types disease will really help us prepare for future changes.”