More than 70 persons participated in the GIHSN 9th Global Annual Meeting (webinar) to discuss flu surveillance and the impact of Covid-19. With site investigators from 23 countries in Northern & Southern hemisphere, influenza experts and external stakeholders, including representatives from World Health Organization, GISAID, the Global Virus Network.
More than 70 experts and investigators from 20 coordinating sites worldwide attended the GIHSN 10-year anniversary webinar, to share and discuss influenza and respiratory virus seasonal results.
30 participants from 11 countries including important experts, representatives from WHO, Bill & Melinda Gates Foundation and US CDC attended the meeting.
In 2012–2013, the GIHSN included 21 hospitals (5 in Spain, 5 in France, 4 in the Russian Federation, and 7 in Turkey).
It was a pilot year for Turkey.
Of 5034 ILI patients included with polymerase chain reaction results, 1545 (30.7%) were positive for influenza.
Influenza A(H1N1), A(H3N2), and both B lineages co-circulated, although distributions varied greatly between coordinating sites and over time.
Two waves of influenza were observed in all sites (some even 3). In a period of 20 weeks all 3 usual influenza strains were related to admissions.
A high level of circulation of B virus was observed mainly in Spain and France. A co-circulation of both Yamagata and Victoria lineages was observed (with a majority of Yamagata lineage).
All age groups were affected by influenza related hospitalization.
Main identified risk factor of an influenza related admission were obesity, pregnancy, cardiovascular disease, and immunodeficiency, increased the risk.
A(H1N1) was the most common influenza strain isolated among hospitalized adults 18–64 years of age at four of five coordinating sites, whereas.
A(H3N2) and B viruses were isolated more often than A(H1N1) in adults ≥65 years of age at all five coordinating sites.
A(H1N1) was rare in those over 75.
B influenza morbidity is significant and B influenza can lead to a large number of hospitalization in adult and elderly.
A total of 16 deaths and 20 intensive care unit admissions were recorded among patients with influenza. In Spain and France 2% and ~3% of patients positive for influenza died in hospital.
Vaccine overall reduce by 1/3 the chance of getting hospitalized for flu related condition.
The vaccine was more effective against B strain (reduced by about half of the hospitalization)
First Year Results of the Global Influenza Hospital Surveillance Network: 2012-2013 Northern hemisphere Influenza Season.
BMC Public Health 2014, 14:564
2012-2013 Seasonal Influenza Vaccine Effectiveness against Influenza Hospitalizations: Results from the Global Influenza Hospital Surveillance Network.
PLoS ONE 9(6): e100497. doi:10.1371/journal.pone.0100497
www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0100497
38 participants from 11 countries including important Flu experts and health representatives from the US-CDC, WHO and the Chinese CDC attended the meeting.
In 2013–2014, the GIHSN included 24 hospitals (6 in Spain, 4 in the Russian Federation, 4 in China, 2 in Brazil and 7 in Turkey). It was a pilot year for Brazil and China.
Of the 5,925 ILI patients included with polymerase chain reaction results, 1,139 (19%) were positive for influenza and 75 (7%) positive for mixed influenza infection.
Influenza A(H1N1), A(H3N2), and both B lineages co-circulated, although distributions varied greatly between coordinating sites and over time. The highest wave of infections started to appear around week 3 and slowly declined after week 12.
H3N2 was dominant in the Russian Federation and Turkey whereas H1N1 positives were found mainly in the Valencia region. Influenza B Yamagata was more present in the Beijing province.
There were only 3 patients positive for B Victoria.
All age groups were affected by influenza related hospitalization.
Pregnancy and obesity are significant risk factors for being admitted in hospital with influenza: A/H1N1, A/H3N2 & B/Yamagata in the pregnant and A/H1N1 in the obese.
H1N1 appeared to be more present in the elderly population (>50 yo) in contrast to H3N2 which was more present in younger population. Influenza B Yamagata appeared to be more present among children and teenagers (5<18yo).
In total there were 82 deaths & 182 ICU admissions. There were no significant differences between positives and negatives for influenza when looking at the patients that died during hospitalization and the ones that were admitted to the ICU.
Preliminary estimates of IVE for the GIHSN 2013/14 season were presented at the meeting.
GIHSN IVE estimates were adjusted by: age (years) and epidemiological week of admission (splines), underlying chronic illnesses.
Adjusted OR (95%CI) results for:
40 participants from 14 countries including flu experts and health representatives from the US-CDC, ECDC and the WHO attended the meeting.
In 2014-2015, the GIHSN included 27 hospitals across 6 countries (Russian Federation, Czech Republic, Turkey, China, Brazil and Spain) in the Northern Hemisphere. It was a pilot year for Czech Republic.
The pooled analysis, however, included only 24 hospitals in 5 countries since Brazil (3 hospitals) kept enrolling patients until end of September in Curitiba, and Fortaleza will stop recruiting in December 2015.
Inpatients were enrolled from November 2014 to May 2015 in the Northern hemisphere.
The highest wave of hospital admissions started during weeks 3-4, slowly declined after week 11, with a peak of number of admissions around weeks 7 and 8, 2015.
Eligible inpatients were >6mo in 23 study sites, or >18yo in one study site.
Although distribution varied amongst sites, inside sites and over time, predominant viruses were influenza A(H3N2) (57%) and influenza B/Yamagata (23%), with a smaller proportion of A(H1N1) and B/Victoria.
A(H3N2) viruses were genetically different from the strain in the vaccine.
In comparison with previous season, an increase of influenza B activity was noticed.
Influenza type B was predominant in Turkey and Moscow whereas influenza A(H3N2) was predominant in China.
All age groups were affected, although 0-4 year-old children were the most affected in Saint Petersburg, Moscow, Turkey and Beijing. In Valencia, there was a high prevalence of influenza cases also amongst >65yo. Therefore, the burden of disease especially increased in children and elderly.
Pregnancy and obesity were confirmed as significant risk factors for hospitalization due to influenza. Pregnancy is an outstanding risk factor for ILI admission: pregnant vs non pregnant OR = 2,8 (CI 1.9 – 4.2). Comorbidity combined with pregnancy increased this risk even more (OR= approximately 7).
More generally, comorbidity increased the risk of influenza and this was the case for all influenza strains.
Preliminary estimates of Influenza Vaccine Effectiveness (IVE) for the GIHSN 2014/15 season were presented at the meeting. Despite the vaccine mismatch, being vaccinated reduced the risk of being admitted to a hospital with influenza by 26%, after adjustment by network.
Other significant results against each of the predominant strains are as follows:
Provide interim robust estimates by increasing frequency of data collection and cleaning.
Keep focused on applying a consistent across-season core protocol in order to be able to pool and compare across seasons.
Created in September 2015, the Foundation for the Influenza Epidemiology was officially launched during the Global Annual Meeting.
