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Incubation period

About: Incubation period is a research topic. Over the lifetime, 1454 publications have been published within this topic receiving 47171 citations.


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Journal ArticleDOI
TL;DR: The results support current proposals for the length of quarantine or active monitoring of persons potentially exposed to SARS-CoV-2, although longer monitoring periods might be justified in extreme cases.
Abstract: Using news reports and press releases from provinces, regions, and countries outside Wuhan, Hubei province, China, this analysis estimates the length of the incubation period of COVID-19 and its pu...

5,215 citations

Journal ArticleDOI
TL;DR: The incubation period falls within the range of 2–14 days with 95% confidence and has a mean of around 5 days when approximated using the best-fit lognormal distribution and it is recommended that the length of quarantine should be at least 14 days.
Abstract: The geographic spread of 2019 novel coronavirus (COVID-19) infections from the epicenter of Wuhan, China, has provided an opportunity to study the natural history of the recently emerged virus. Using publicly available event-date data from the ongoing epidemic, the present study investigated the incubation period and other time intervals that govern the epidemiological dynamics of COVID-19 infections. Our results show that the incubation period falls within the range of 2–14 days with 95% confidence and has a mean of around 5 days when approximated using the best-fit lognormal distribution. The mean time from illness onset to hospital admission (for treatment and/or isolation) was estimated at 3–4 days without truncation and at 5–9 days when right truncated. Based on the 95th percentile estimate of the incubation period, we recommend that the length of quarantine should be at least 14 days. The median time delay of 13 days from illness onset to death (17 days with right truncation) should be considered when estimating the COVID-19 case fatality risk.

1,222 citations

Journal ArticleDOI
TL;DR: A systematic review of the literature on nine respiratory viral infections of public-health importance found the median incubation period to be 5·6 days, with 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.
Abstract: Summary 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.

724 citations

Journal ArticleDOI
TL;DR: Temperature-induced variations in the vector efficiency of Ae.
Abstract: The effect of temperature on the ability of Aedes aegypti to transmit dengue (DEN) 2 virus to rhesus monkeys was assessed as a possible explanation for the seasonal variation in the incidence of dengue hemorrhagic fever in Bangkok, Thailand. In two laboratory experiments, a Bangkok strain of Ae. aegypti was allowed to feed upon viremic monkeys infected with DEN-2 virus. Blood-engorged mosquitoes were separated into two groups and retained at constant temperatures. Virus infection and transmission rates were determined for Ae. aegypti at intervals ranging from 4 to 7 days during a 25-day incubation period. Results of the first experiment for mosquitoes infected with a low dose of DEN-2 virus and maintained at 20,24,26, and 3O"C, indicated that the infection rate ranged from 25% to 75% depending on the incubation period. However, DEN-2 virus was transmitted to monkeys only by Ae. aegypti retained at 30°C for 25 days. In the second experiment, the infection rate for Ae. aegypti that ingested a higher viral dose, and incubated at 26, 30, 32, and 35°C ranged from 67% to 95%. DEN-2 virus was transmitted to monkeys only by mosquitoes maintained at L 30°C. The extrinsic incubation period was 12 days for mos- quitoes at 3O"C, and was reduced to 7 days for mosquitoes incubated at 32°C and 35°C. These results imply that temperature-induced variations in the vector efficiency of Ae. aegypti may be a significant determinant in the annual cyclic pattern of dengue hemorrhagic fever epidemics in-Bangkok.

709 citations

Journal ArticleDOI
TL;DR: An antigen that reacted in the immunodiffusion test with serum from multiply transfused patients was detected in the blood during the incubation period prior to the onset of major chemical or clinical abnormalities, suggesting this antigen is specific for serum hepatitis virus.
Abstract: The aim of the following experiments was to provide an objective immunologic criterion for the diagnosis of serum hepatitis, as well as a possible means of screening for carriers of the agent of this disease. An antigen that reacted in the immunodiffusion test with serum from multiply transfused patients was detected in the blood during the incubation period prior to the onset of major chemical or clinical abnormalities. Double blind experiments suggest that this antigen is specific for serum hepatitis virus. Materials and Methods.-Clinical specimens: Sera from cases of transfusion-induced viral hepatitis, which we have collected, were obtained as part of a long-term study involving biweekly follow-up of transfused patients at The New York Hospital. Patients volunteering to participate in this study provided blood samples prior to transfusion and at least biweekly for a period of 6 months or more following transfusion. Test serum: The reference \"antiserum\" used in the majority of the studies to be described, hereinafter referred to as serum S, was obtained from a 24-year-old male patient with hemophilia who has received more than 10,000 units of blood, fresh-frozen plasma, and cryoprecipitate during the course of treatment for bleeding episodes. He has had no episodes of icteric hepatitis, but it was presumed that he had been multiply exposed to the virus or viruses of serum hepatitis. Serum S was chosen for these studies because the patient's multiple exposure was thought to ensure a hyperimmune status. Subsequently, four other sera from multiply transfused patients have been found to react in a manner similar to serum S. For some experiments, the serum was concentrated by ethanol fractionation. To each milliliter of serum to be concentrated, 8 ml of 30% ethanol in 0.1 Ml NaCl, 0.01 M tris(hydroxymethyl)aminomethane (Tris), 0.001 Ml ethylenediaminetetraacetate (EDTA), (pH 7.0 at -7oC) were added. This mixture was held at -70C and lyophilized. The dried globulin fraction was then rehydrated with distilled water to 0.1 the original volume of serum employed. Immunodiffusion technique: Double diffusion in agar gel was done by a micro-Ouchterlony technique.1 Nonspecific precipitation reactions between adjacent wells were eliminated by the use of 0.9% agarose dissolved in a buffer composed of 0.1 M NaCl, 0.01 M Tris (pH 7.6 at 250C), and 0.001 M EDTA containing 1 mg/ml protamine sulfate. Protamine sulfate has been recently suggested as a means of decreasing virus-agar interaction.2 Plates were incubated in a humid atmosphere at room temperature and read daily for 7 days. Strong reactions were evident after overnight incubation, while weaker reactions required 2 or 3 days' incubation and intensified for several days. Clinical chemical methods: Serum glutamic pyruvic transaminase (SGPT) was assayed by a kinetic spectrophotometric method with the Gilford multiple method sample recording spectrophotometer.3 Serum lactic dehydrogenase (LDH) enzymes were assayed by the method of Amador et al.4 with the same instrument. Serum LDH isoenzymes were separated by thin agar gel electrophoresis and quantitated fluorometrically.5 Results.-Demonstration of an antigen appearing in the blood during the incubation period of serum hepatitis: Failure in the past to isolate a causative virus from serum hepatitis could possibly be attributed to the fact that most isolation attempts have been carried out with specimens obtained early in the clinical course of the disease, at what is actually a late stage of the infection due to the

686 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023107
2022232
202163
202089
201941
201832