Elsevier

Medical Hypotheses

Volume 86, January 2016, Pages 104-119
Medical Hypotheses

Seasonality and selective trends in viral acute respiratory tract infections

https://doi.org/10.1016/j.mehy.2015.11.005Get rights and content

Abstract

Influenza A and B, and many unrelated viruses including rhinovirus, RSV, adenovirus, metapneumovirus and coronavirus share the same seasonality, since these viral acute respiratory tract infections (vARIs) are much more common in winter than summer. Unfortunately, early investigations that used recycled “pedigree” virus strains seem to have led microbiologists to dismiss the common folk belief that vARIs often follow chilling. Today, incontrovertible evidence shows that ambient temperature dips and host chilling increase the incidence and severity of vARIs. This review considers four possible mechanisms, M1 - 4, that can explain this link: (M1) increased crowding in winter may enhance viral transmission; (M2) lower temperatures may increase the stability of virions outside the body; (M3) chilling may increase host susceptibility; (M4) lower temperatures or host chilling may activate dormant virions. There is little evidence for M1 or M2, which are incompatible with tropical observations. Epidemiological anomalies such as the repeated simultaneous arrival of vARIs over wide geographical areas, the rapid cessation of influenza epidemics, and the low attack rate of influenza within families are compatible with M4, but not M3 (in its simple form). M4 seems to be the main driver of seasonality, but M3 may also play an important role.

Abbreviations

HEF
hemagglutinin-esterase-fusion protein
HFMD
hand, foot and mouth disease
PCR
polymerase chain reaction
RSV
respiratory syncytial virus
Ts or ts
temperature-sensitive
vARI or vARIs
viral acute respiratory tract infection or infections

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No grants or funding of any kind were received for this project.

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