Objectives: No studies have examined longitudinal patterns of naturally exhaled SARS-CoV-2 RNA viral load (VL) during acute infection. We report this using facemask sampling (FMS) and assessed the relationship between emitted RNA VL and household transmission.
Methods: Between December 2020 and February 2021, we recruited participants within 24 hours of a positive RT-qPCR on upper respiratory tract sampling (URTS) (day 0). Participants gave FMS (for 1 hour) and URTS (self-taken) on seven occasions up to day 21. Samples were analysed by RT-qPCR (from sampling matrix strips within the mask) and symptom diaries were recorded. Household transmission was assessed through reporting of positive URTS RT-qPCR in household contacts.
Results: Analysis of 203 FMS and 190 URTS from 34 participants showed that RNA VL peaked within the first 5 days following sampling. Concomitant URTS, FMS RNA VL, and symptom scores, however, were poorly correlated, but a higher severity of reported symptoms was associated with FMS positivity up to day 5. Of 28 participants who had household contacts, 12 (43%) reported transmission. Frequency of household transmission was associated with the highest (peak) FMS RNA VL obtained (negative genome copies/strip: 0% household transmission; 1 to 1000 copies/strip: 20%; 1001 to 10 000 copies/strip: 57%; >10 000 copies/strip: 75%; p = 0.048; age adjusted OR of household transmission per log increase in copies/strip: 4.97; 95% CI, 1.20-20.55; p = 0.02) but not observed with peak URTS RNA VL.
Discussion: Exhaled RNA VL measured by FMS is highest in early infection, can be positive in symptomatic patients with concomitantly negative URTS, and is strongly associated with household transmission.
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http://dx.doi.org/10.1016/j.cmi.2022.07.005 | DOI Listing |
N Engl J Med
December 2024
From the Influenza Division, Centers for Disease Control and Prevention, Atlanta (S.G., K.R., A.C., K.K., C.T.D., M.K.K., S. Ellington, A.M.M., A.B., J.R.B., M.B., M.A.J., M.R.-C., E.B., T.T.S., T.M.U., V.G.D., C.R., S.J.O.); California Department of Public Health, Richmond (E.L.M., S.Z., V.K., D.A.W.); the Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta (S.Z., C.D.); Colorado Department of Public Health and Environment, Denver (C.D., A.K., M.O.); Mid-Michigan District Health Department, Stanton (J.M.); Michigan Department of Health and Human Services, Lansing (S. Eckel); Missouri Department of Health and Senior Services, Jefferson City (J.G., G.T.); Benton-Franklin Health District, Kennewick, WA (S.K.); Washington State Department of Health, Tumwater (A.U.); and Texas Department of State Health Services, Austin (E.R.G., C.A.H.).
Background: Highly pathogenic avian influenza A(H5N1) viruses have caused widespread infections in dairy cows and poultry in the United States, with sporadic human cases. We describe characteristics of human A(H5N1) cases identified from March through October 2024 in the United States.
Methods: We analyzed data from persons with laboratory-confirmed A(H5N1) virus infection using a standardized case-report form linked to laboratory results from the Centers for Disease Control and Prevention influenza A/H5 subtyping kit.
PLOS Glob Public Health
December 2024
Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
Knowing when and where infected mosquitoes bite is required for estimating accurate measures of malaria risk, assessing outdoor exposure, and designing intervention strategies. This study combines secondary analyses of a human behaviour survey and an entomological survey carried out in the same area to estimate human exposure to malaria-infected Anopheles mosquitoes throughout the night in rural villages in south-eastern Tanzania. Mosquitoes were collected hourly from 6PM to 6AM indoors and outdoors by human landing catches in 2019, and tested for Plasmodium falciparum sporozoite infections using ELISA.
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December 2024
Department of Pediatrics and Child Health Nursing, College of Medicine and Health Sciences, Bahir Dar, Ethiopia.
Introduction: Insecticide-treated bed nets are often used as a physical barrier to prevent infection of malaria. In Sub-Saharan Africa, one of the most important ways of reducing the malaria burden is the utilization of insecticide-treated bed nets. However, there is no sufficient information on the utilization of insecticide-treated bed nets and their associated factors in Ethiopia.
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December 2024
Centre for Infectious Diseases Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands.
Understanding the impact of different types of social interactions is key to improving epidemic models. Here, we use extensive registry data-including PCR test results and population-level networks-to investigate the impact of school, family, and other social contacts on SARS-CoV-2 transmission in the Netherlands (June 2020-October 2021). We isolate and compare different contexts of potential SARS-CoV-2 transmission by matching pairs of students based on their attendance at the same or different primary school (in 2020) and secondary school (in 2021) and their geographic proximity.
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December 2024
Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Data Science Institute, Hasselt University, Hasselt, Belgium.
In this study, we employed a modeling approach to describe how changes in age-specific epidemiological characteristics, such as behaviour, i.e. contact patterns, susceptibility and infectivity, influence the basic reproduction number , while accounting for heterogeneity in transmission.
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