Influenzanet is a system to monitor the activity of influenza-like-illness (ILI) with the aid of volunteers via the internet

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The Seventh Framework Programme (FP7) bundles all research-related EU initiatives.

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Participating countries and volunteers:

The Netherlands 0
Belgium 0
Portugal 0
Italy 0
Great Britain 10916
Sweden 3559
Germany 0
Austria 0
Switzerland 0
France 6674
Spain 0
Ireland 0
Denmark 0
InfluenzaNet is a system to monitor the activity of influenza-like-illness (ILI) with the aid of volunteers via the internet. It has been operational in The Netherlands and Belgium (since 2003), Portugal (since 2005) and Italy (since 2008), and the current objective is to implement InfluenzaNet in more European countries.

In contrast with the traditional system of sentinel networks of mainly primary care physicians coordinated by the European Influenza Surveillance Scheme (EISS), InfluenzaNet obtains its data directly from the population. This creates a fast and flexible monitoring system whose uniformity allows for direct comparison of ILI rates between countries.

Any resident of a country where InfluenzaNet is implemented can participate by completing an online application form, which contains various medical, geographic and behavioural questions. Participants are reminded weekly to report any symptoms they have experienced since their last visit. The incidence of ILI is determined on the basis of a uniform case definition.

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Weekly Flu and Covid-19 Surveillance Report is now available via this link

Covid19 surveillance using the Flusurvey surveillance webtool began on the 18th of March following evidence of community transmission of coronavirus in the UK. The routine influenza-like-illness (ILI) symptoms questionnaire was adapted to capture additional respiratory symptoms, exposure risks and healthcare seeking behaviours related to coronavirus. The data collated from this system are frequently being analysed and now forms part of UK Health Security Agency (UKHSA) Weekly National Influenza and Covid-19 Surveillance Report.

The 2021/22 flu season has now began, we continue to report both influenza like illness (ILI) and covid-19 related symptoms through the surveillance system. Data represents UK residents who have registered to participate during the survey period.

During week 11,  there were 2,574 participants completing the weekly symptoms questionnaire of which  202 (7.9%) reported fever or cough and 61 (2.4%) reported influenza like illness (ILI). There was a marked increase in Covid-19 related symptoms and ILI activity amongst respondents completing the symptoms questionnaire and has been increasing since week 8. Figure 1 shows the proportion of individuals reporting ILI and Covid-19 related symptoms as well as how flusurvey respondent use the available healthcare services during this outbreak (Detailed analysis of the data we collect will be shared when they become publicly available). Data presented is collated weekly on Wednesdays and represents information reported up to and including Sunday.

2021/22 Covid 19/ILI Provisional Data

Figure 1

For archived Flusurvey results click here

2019/20 Flusurvey Provisional Results

The 2019/20 Flusurvey officially started on the 13th Nov 2019 (week 46), recruitment of eligible participant ended on the 25th of December, 2019 (week 52). Data from participants who registered on the platform during the time frame were included in the analysis for reporting weekly ILI incidence during the flu season. Thank you to everyone who signed up to participate. As always, we will be sending out weekly reminder emails to encourage you to complete the questionnaire telling us if you are unwell or not.
The flu season data was completed during week 20, there were 2,076 users completing the weekly symptoms questionnaire completing the weekly symptoms questionnaire. The overall ILI rate (all age groups) of influenza-like-illness (ILI) was 9.2 per 1,000 (19/2,076 people reported at least 1 ILI), with the highest rate seen in under 20-44 year olds (21.9 per 1,000). The weekly national influenza report showed  influenza activity has been decreasing across most influenza indicators  and now below baseline levels in week 5 (PHE - National Influenza Report). 

2017/18 Flusurvey Results

The 2017/18 Flusurvey commenced on 18th of October, 2017 (week 42) following established Influenza activity in the UK and was completed on 16th May, 2018 (week 20) with a total of 7,516 volunteers registering on the platform; updating their profiles and completing at least one symptoms questionnaire. During the 2017/18 influenza season, weekly symptomatic questionnaires were completed and data was analysed using STATA v 13. Data collected through the platform contributes to the routine surveillance activities carried out by Public Health England (PHE) to monitor the burden of influenza-like-illness (ILI) in the community using non-traditional surveillance methods.
Influenza activity continues to circulate but now decreasing across most disease indicators with Flu A and B co-circulating. (Data from PHE national weekly flu report). The national influenza weekly report can be viewed here. Among Flusurvey participants, there were 2,306 users completing the weekly symptoms questionnaire in week 15. The overall ILI rate (all age groups) was 18.2 per 1,000 (42/2,306 people reported at least 1 ILI) (Figure 1), with the highest rate seen in under 20-44 year olds (38.5 per 1,000) Data not shown.

2016/17 Flusurvey Results

This report describes the final analysis of the 2016/17 flusurvey which commenced on the 2nd of November, 2016 (week 44) following established influenza circulation and was completed on 7th of May, 2017 (week 18). It forms part of the routine surveillance duties carried out by Public Health England (PHE) to monitor the burden of influenza-like-illness in the community using non-traditional surveillance methods. In total, 4,137 individuals registered to participate in the weekly survey of which 4,040 (97.7%) completed at least one symptoms survey questionnaire suggesting a high engagement rate with its users. During the survey period, 52,332 real-time flu related symptoms data were reported, figure 1 shows the distribution of registered participants and those completing the weekly symptoms questionnaire up to and including week 18 which indicates an average response rate of 60.0%.
Figure 1: Number of registered participants compared to those completing the symptoms survey each week up to week 18, 2016/17
The cumulative influenza-like-illness clinical attack rate among active participants (those who completed at least 3 symptoms questionnaire) over the survey period was 3.3%. The weekly incidence rate by age group is presented in Figure 2 and shows peak ILI activity among participants in week 52. On average, the <20 years old age group reported higher ILI for the most of the survey period. These findings were not consistent with the PHE influenza surveillance data, which showed that the highest disease burden was reported in the 65+ age group with influenza A(H3N2) being the dominant circulating strain in 2016/17.
Figure 2: FluSurvey Overall ILI incidence and by age group, UK - up to week 18, 2016/17

Characteristics of Flusurvey Participants

There were 4,040 participants who completed at least one week's symptoms questionnaire during the survey, 65.3% of whom were women (Figure 3). The mean age of participants was 48.7 years higher than last season which was 42.7 years. The age distribution of respondent was not representative of the national average estimates (Figure 4), as the survey suggested more people aged 35 years and over; classified as highly educated and in full employment were more likely to sign up and participate in the survey. Increasing the number of households with children (only 5.0% of participants were <18 years old) participating in the survey is important to enable us better understand the dynamics of influenza transmission within this population given that children are known disease drivers

Figure 3: Gender distribution of participants, week 42 2016 to week 18 2017
Figure 4: Age Group of participants with national estimates, 2016/17
Figure 5: Employment status of respondents, 2016-17
Figure 6: Mode of transport of participants, 2016-17

More than half (57.6%) of survey participants reported using their car as their main mode of transportation compared to public transport (21.3%) or walking (14.2%)

Figure 7: Where do Flusurvey participants come from?

Figure 7 shows which region Flusurvey participants reported they reside. The highest number of respondents lived in the South East and London region and were very well represented in the survey. However, only a hand full of respondents were living in Isle of Man, Channel Island and Northern Ireland. We will be exploring ways to engage more people to register and participate in the survey in the coming season

Figure 8: Most commonly reported flu symptoms, 2016-17

Above you can see the most commonly reported symptoms amongst cases during the flu season. Sudden onset of symptoms and runny nose were the most frequently reported symptoms while chest pain and fever were least amongst Flusurvey participants.

Figure 7: Weekly ILI rates by age groups in 2015/16, results up to week 20

Data up to week 20 shows that ILI incidence per 1,000 among flusurvey participants peaked at week 8. The highest ILI incidence was observed among 0-19 year olds. 

Note: data for wk 7 is an average of data collected in wk6 and wk8 since no data was available
Figure 8: Weekly ILI incidence per 1000, 2015/16
Figure 9: The reasons respondnents gave for receiving or not receiving the 2015/16 flu vaccine.

1775 (43.3%) participant reported receiving the 2015/16 influenza vaccine. The reason participants gave for receiving or not receiving the flu vaccine are presented in the figure above. Encouragingly, a relatively small proportion of people had negative attitudes about the influenza vaccine (i.e. concerns around safety, side effects or efficacy of vaccine) while increasing vaccine availability and improving convenience of administration (e.g. in the work place) would increase vaccine uptake in the general population.

Figure 10: Healthcare seeking behaviours reported by participants, 2015/16

This figure above shows the proportion of Flusurvey participants reporting a flu-like illness in the 2015/16 flu season and who sought care from a health professional either by calling a service or visiting, or what medication they may have taken. It is important to note how the proportion of participants who reported taking painkillers were similar to that of those who did not seek healthcare services.