Incubation periods of acute respiratory viral infections: A systematic review

Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
The Lancet Infectious Diseases (Impact Factor: 22.43). 06/2009; 9(5):291-300. DOI: 10.1016/S1473-3099(09)70069-6
Source: PubMed


Knowledge of the incubation period is essential in the investigation and control of infectious disease, but statements of incubation period are often poorly referenced, inconsistent, or based on limited data. In a systematic review of the literature on nine respiratory viral infections of public-health importance, we identified 436 articles with statements of incubation period and 38 with data for pooled analysis. We fitted a log-normal distribution to pooled data and found the median incubation period to be 5.6 days (95% CI 4.8-6.3) for adenovirus, 3.2 days (95% CI 2.8-3.7) for human coronavirus, 4.0 days (95% CI 3.6-4.4) for severe acute respiratory syndrome coronavirus, 1.4 days (95% CI 1.3-1.5) for influenza A, 0.6 days (95% CI 0.5-0.6) for influenza B, 12.5 days (95% CI 11.8-13.3) for measles, 2.6 days (95% CI 2.1-3.1) for parainfluenza, 4.4 days (95% CI 3.9-4.9) for respiratory syncytial virus, and 1.9 days (95% CI 1.4-2.4) for rhinovirus. When using the incubation period, it is important to consider its full distribution: the right tail for quarantine policy, the central regions for likely times and sources of infection, and the full distribution for models used in pandemic planning. Our estimates combine published data to give the detail necessary for these and other applications.

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Available from: Justin Lessler, Oct 09, 2015
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    • "In addition, the short follow-up duration of this trial means there is a possible failure to detect some infections. The incubation period of respiratory viruses may range from less than 2 days (e.g., rhinovirus and influenza) to more than 5 days (adenovirus, MERS-CoV) [30] [31]. However, it is believed that post-Hajj Health diaries will reduce this shortcoming to some extent. "
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    ABSTRACT: Background Cost-effective interventions are needed to control the transmission of viral respiratory tract infections (RTIs) in mass gatherings. Facemasks are a promising preventive measure, however, previous studies on the efficacy of facemasks have been inconclusive. This study proposes a large-scale facemask trial during the Hajj pilgrimage in Saudi Arabia and presents this protocol to illustrate its feasibility and to promote both collaboration with other research groups and additional relevant studies. Methods/design A cluster-randomised controlled trial is being conducted to test the efficacy of standard facemasks in preventing symptomatic and proven viral RTIs among pilgrims during the Hajj season in Mina, Mecca, Saudi Arabia. The trial will compare the ‘supervised use of facemasks’ versus ‘standard measures’ among pilgrims over several Hajj seasons. Cluster-randomisation will be done by accommodation tents with a 1:1 ratio. For the intervention tents, free facemasks will be provided to be worn consistently for 7 days. Data on flu-like symptoms and mask use will be recorded in diaries. Nasal samples will be collected from symptomatic recruits and tested for nucleic acid of respiratory viruses. Data obtained from questionnaires, diaries and laboratory tests will be analysed to examine whether mask use significantly reduces the frequency of laboratory-confirmed respiratory viral infection and syndromic RTI as primary outcomes. Conclusions This trial will provide valuable evidence on the efficacy of standard facemask use in preventing viral respiratory tract infections at mass gatherings. This study is registered at the Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN: ACTRN12613001018707 (
    Journal of Epidemiology and Global Health 10/2014; 5(2). DOI:10.1016/j.jegh.2014.08.002
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    • "The present study utilized a case-crossover design which is most suitable for studying relations with the following characteristics: 1) the individual exposure varies within short time intervals; 2) the disease has abrupt onset and short latency for detection; and 3) the induction period is short [17]. For ambient temperature and AH the hazard period was defined as three days preceding the visit to the clinic for a respiratory infection (and when virological samples were collected) on the basis of the estimated incubation period of 1–2 days for influenza [18]. A symmetric bidirectional selection of two reference periods shortly before and after the hazard period was utilized [19]. "
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    ABSTRACT: Both temperature and humidity may independently or jointly contribute to the risk of influenza infections. We examined the relations between the level and decrease of temperature, humidity and the risk of influenza A and B virus infections in a subarctic climate. We conducted a case-crossover study among military conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training period and identified 66 influenza A and B cases by PCR or serology. Meteorological data such as measures of average and decline in ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods, prior and after the onset were obtained. The average temperature preceding the influenza onset was -6.8 +/- 5.6[degree sign]C and AH 3.1 +/- 1.3 g/m3. A decrease in both temperature and AH during the hazard period increased the occurrence of influenza so that a 1[degree sign]C decrease in temperature and 0.5 g decrease per m3 in AH increased the estimated risk by 11% [OR 1.11 (1.03 to 1.20)] and 58% [OR 1.58 (1.28 to 1.96)], respectively. The occurrence of influenza infections was positively associated with both the average temperature [OR 1.10 per 1[degree sign]C (95% confidence interval 1.02 to 1.19)] and AH [OR 1.25 per g/m3 (1.05 to 1.49)] during the hazard period prior to onset. Our results demonstrate that a decrease rather than low temperature and humidity per se during the preceding three days increase the risk of influenza episodes in a cold climate.
    Environmental Health 03/2014; 13(1):22. DOI:10.1186/1476-069X-13-22 · 3.37 Impact Factor
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    • "In our study 50% of hospital-acquired confirmed influenza declared their symptoms 24 hours after admission. For influenza, it has been suggested that 30% of infected persons may develop symptoms within one day, and 80% within two days, after infection, with an average incubation period of 1.9 days [14,15]. We, therefore, consider that HA-ILI may be the result of infection by the virus in hospital within the first day but also within the second day of admission. "
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    ABSTRACT: Data on influenza in the healthcare setting are often based on retrospective investigations of outbreaks and a few studies described influenza during several consecutive seasons.The aim of the present work is to report data on influenza like illness (ILI) and influenza from 5-year prospective surveillance in a short-stay geriatrics unit. A short stay geriatrics unit underwent 5 years of ILI surveillance from November 2004 to March 2009, with the aim of describing ILI in a non-outbreak context. The study was proposed to patients who presented ILI, defined as fever >37.8[degree sign]C or cough or sore throat. Among 1,353 admitted patients, 115 presented an ILI, and 34 had hospital-acquired ILI (HA-ILI). Influenza was confirmed in 23 patients, 13 of whom had been vaccinated. Overall attack rates were 2.78% and 0.02% for HA-ILI and HA-confirmed influenza respectively, during the 5 seasons. This 5-year surveillance study supports the notion that influenza infections are common in hospitals, mostly impacting the elderly hospitalized in short-stay units. It highlights the need for appropriate control measures to prevent HA-ILI in geriatric units and protect elderly patients.
    BMC Research Notes 02/2014; 7(1):99. DOI:10.1186/1756-0500-7-99
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