Seasonal rhythms are endogenous timing mechanisms that allow animals living at temperate latitudes to synchronize their physiology to the seasons. Human viral respiratory disease is prevalent in the ...winter at temperate latitudes, but the role of endogenous mechanisms in these recurring annual patterns is unclear. The Common Cold Project is a repository of data describing the experimental viral challenge of 1,337 participants across the seasons of the year. We report a secondary analysis of these data to investigate if susceptibility to the common cold is associated with day length. The majority of the participants (78%) showed signs of infection but only 32% developed clinical signs of disease, and the probability of infection was significantly higher in longer day lengths (summer), but the disease was more likely in short (winter) day lengths. The persistence of winter disease patterns in experimental conditions supports the role of endogenous seasonality in human susceptibility to viral infection.
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•Outbreaks of viral respiratory disease recur in winter in the northern hemisphere•In controlled experiments, common cold infection was more likely in summer•Infection was more likely to progress to the development of cold in winter•Innate seasonality of human immunity could affect the prevalence of the common cold
Chronobiology; Virology
Background Prisoners are recognised as a high-risk population and prisons as high-risk locations for the transmission of hepatitis c virus (HCV) infection. Injecting drug use (IDU) is the main driver ...of HCV infection in prisoners and harm reduction services are often suboptimal in prison settings. HCV prevalence and incident data in prisoners is incomplete which impacts the public health opportunity that incarceration provides in identifying, treating and preventing HCV infection. The aim of this study is to identify new HCV infection and associated risk factors in an Irish male prison. Methods We conducted a follow up (18-month) cohort study on prisoners who had previously tested negative, self-cleared or had been successfully treated for HCV infection. We conducted the study in a male medium security prison located in Dublin Ireland (Mountjoy Prison) using HCV serology, a review of medical records and a researcher-administered questionnaire. Results 99 prisoners with a mean age of 33.2 yrs. participated in the study and 82(82.8%) completed a research-administered questionnaire. Over half (51%) had a history of drug use from a young age (14.8 yrs.), 49.9% a history of heroin use and 39% a history of IDU. The prevalence of HIV and hepatitis B virus core antibody was 3% and HCV antibody was 22.2%. No new HCV infections were identified in those who had never been infected (n = 77), had self-cleared (n = 9) or achieved sustained virological response (n = 12). Small numbers of prisoners continued to engage in risk-behaviour including, IDU both in the prison (n = 2) and the community (n = 3), sharing syringes (n = 1) and drug taking paraphernalia (n = 6) and receiving non-sterile tattoos (n = 3). Conclusion Despite the high numbers of Irish prisoners with a history of IDU and HCV infection, new HCV infection is low or non-existent in this population. Small numbers of prisoners continue to engage in risk behaviour and larger studies are required to further understand HCV transmission in this cohort in an Irish and international context. Keywords: Hepatitis C, HCV, Prisoner, Prison, Incident, Harm reduction, Medication assisted treatment, MAT
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