About the Authors

Anette Hulth

anette.hulth@smi.se

Affiliation Department of Epidemiology, Swedish Institute for Infectious Disease Control, Solna, Sweden

Gustaf Rydevik

Affiliation Department of Epidemiology, Swedish Institute for Infectious Disease Control, Solna, Sweden

Annika Linde

Affiliation Department of Epidemiology, Swedish Institute for Infectious Disease Control, Solna, Sweden

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: AH GR. Performed the experiments: AH GR. Analyzed the data: AH GR AL. Wrote the paper: AH GR AL.