Self-sampling for analysis of respiratory viruses in a large-scale epidemiological study in Sweden

Abstract

Viral diagnosis of respiratory tract infections has so far required sampling by health professionals, hampering large-scale epidemiological studies of virus-specific disease outcomes. As part of a population-based, prospective study of work-related risk factors for transmission of viral infections (SWEDE-I), we developed a scheme for self-sampling with nasal swabs. Random selection from the gainfully employed population of a medium-sized town in central Sweden resulted in a study cohort of 2,237 men and women aged 25 to 63 years. From September 2011 through May 2012, the cohort reported all instances of respiratory tract infection or gastroenteritis and participants concomitantly sent self-sampled nasal swabs for analysis using regular mail. Diagnosis of 14 viruses was performed. A total of 1,843 samples were received. The week-wise average delay between disease onset and arrival of the specimens at the laboratory varied between four and six days, and the corresponding median delay was between 3.5 and six days. In line with previous community-based studies, picorna-and coronaviruses dominated in specimens obtained from the self-sampling scheme. The results of self-sampling were contrasted to those from contemporaneous routine clinical sampling, on the same age group, in the adjacent Stockholm county. Although higher proportions of positive samples for respiratory syncytial virus and influenza were observed in the clinical sampling scheme, estimations of seasonality for influenza A and picornaviruses derived from both schemes were similar. Our findings show that nasal self-sampling is feasible in large-scale surveillance of respiratory infections and opens new prospects for populationbased, virologically verified research on virus spread, burden of disease, and effects of environmental factors or interventions.

Feasibility study for the use of self‐collected nasal swabs to identify pathogens among participants of a population‐based surveillance system for acute respiratory infections (GrippeWeb‐Plus)—Germany, 2016

“…The viruses most frequently identified were rhino‐/enterovirus, coronaviruses, influenza viruses as well as bocavirus. Except for bocavirus which was not tested in other studies, this finding is in broad agreement with results published by Goff (USA, 2013/2014) and Plymouth (Sweden, 2001/2012) . However, pathogens that are rather detectable in the lower respiratory tract, perhaps particularly bacteria, may not be detectable through this method.…”

“…During this study, a large variety of viruses was detected. More than 70% of swabs from symptomatic participants yielded at least one pathogen, more than in studies with a similar diagnostic spectrum (36%; 48%). The viruses most frequently identified were rhino‐/enterovirus, coronaviruses, influenza viruses as well as bocavirus.…”

High added value of a population-based participatory surveillance system for community acute gastrointestinal, respiratory and influenza-like illnesses in Sweden, 2013–2014 using the web

“…This may have affected the acceptance to join the project and, consequently, the representativeness of the cohort. However, participation was similar to other recent cohort studies [12, 13], including the 2008–2009 UK Infectious Intestinal Disease study 2 (IID2) and the 2011–2012 Swedish study of work environment and disease epidemiology-infections (SWEDE-I), which had recruitment proportions ranging from 9% to 16%. However, it was lower than older, non-web-based European cohorts: the recruitment proportion of the Infectious intestinal disease study (IID1) conducted in the UK in the 1990s was 35% [14], and for the Sensor study [6] in The Netherlands in 1998–1999, it was 42%.…”

The acceptability and validity of self‐collected nasal swabs for detection of influenza virus infection among older adults in Thailand

“…After collection, swabs may be returned to study staff by mail, dropped off or collected at home by study staff. Several studies have shown self‐collection of nasal swabs among adults to be a feasible and reliable method for ARI surveillance . The Flu Watch Cohort Study followed community cohorts in England over six successive influenza seasons and successfully obtained diagnostic nasal specimens through self‐collection of nasal swabs for more than 85% of ARI episodes .…”

“…The Flu Watch Cohort Study followed community cohorts in England over six successive influenza seasons and successfully obtained diagnostic nasal specimens through self‐collection of nasal swabs for more than 85% of ARI episodes . Additionally, a recent study among Swedish adults used nasal self‐swab samples mailed in by participants for virus detection and found that the influenza‐positive test results could be used to measure influenza seasonality . However, to our knowledge, there has not yet been a specific evaluation of self‐collection of nasal swabs by older adults, who may have reduced mobility and cognitive function that could limit their ability to collect valid nasal swabs.…”