H5N1

Ten years ago: The first news of H1N1

Ten years ago, this blog was just about all H5N1, and I had a lot of news on cases in Indonesia, Egypt, and Pakistan. Then, on April 21, I posted an item by Helen Branswell, then with The Canadian Press: Branswell on the California swine-flu cases. Excerpt and then a comment:

U.S. public health authorities are investigating two cases of swine flu in unrelated children in California, a development that has officials in Canada and elsewhere on alert.   

Discovery of the two cases, in children who apparently had no contact with pigs or with each other, suggests there probably has been some person-to-person spread of swine flu viruses, officials of the U.S. Centers for Disease Control said Tuesday.  

Whether the viruses continue to spread isn't currently known.   

"The investigation is not finished. It's ongoing. But of course not having that direct swine link does raise additional questions and does suggest that there may have been human-to-human transmission. And so it basically ratchets it (concern) up a bit," said Dr. Nancy Cox, head of the CDC's influenza division.  "I think this is one of those situations where everyone will want to stay tuned."  

U.S. officials notified the World Health Organization of the cases last Friday, as required under the International Health Regulations. That treaty stipulates that countries must notify the WHO when they see cases of infectious diseases that pose an international threat, such as novel subtypes of influenza with pandemic potential. 

The next day saw a "swine flu" post from the much-missed Revere, Flublogia's resident grownup in those days. Although I didn't post it, the CDC also issued a notice about it on April 22, and on the 23rd the Globe and Mail warned that Canadians returning from Mexico should be alert to the symptoms of "Mexican flu."

What followed was not so much mission creep as mission drag, as a real live serious novel influenza hauled me and the rest of Flublogia out of our comfortable niche and into a much more complicated world. That drag continues.

Children under 10 years of age were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic in Canada

Via Eurosurveillance: Children under 10 years of age were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic in Canada: ‎possible cohort effect following the 2009 influenza pandemic. The abstract:

Introduction 

Findings from the community-based Canadian Sentinel Practitioner Surveillance Network (SPSN) suggest children were more affected by the 2018/19 influenza A(H1N1)pdm09 epidemic. 

Aim 

To compare the age distribution of A(H1N1)pdm09 cases in 2018/19 to prior seasonal influenza epidemics in Canada. 

Methods 

The age distribution of unvaccinated influenza A(H1N1)pdm09 cases and test-negative controls were compared across A(H1N1)pdm09-dominant epidemics in 2018/19, 2015/16 and 2013/14 and with the general population of SPSN provinces. Similar comparisons were undertaken for influenza A(H3N2)-dominant epidemics.  

Results 

In 2018/19, more influenza A(H1N1)pdm09 cases were under 10 years old than controls (29% vs 16%; p < 0.001). In particular, children aged 5–9 years comprised 14% of cases, greater than their contribution to controls (4%) or the general population (5%) and at least twice their contribution in 2015/16 (7%; p < 0.001) or 2013/14 (5%; p < 0.001). Conversely, children aged 10–19 years (11% of the population) were under-represented among A(H1N1)pdm09 cases versus controls in 2018/19 (7% vs 12%; p < 0.001), 2015/16 (7% vs 13%; p < 0.001) and 2013/14 (9% vs 12%; p = 0.12). 

Conclusion 

Children under 10 years old contributed more to outpatient A(H1N1)pdm09 medical visits in 2018/19 than prior seasonal epidemics in Canada. In 2018/19, all children under 10 years old were born after the 2009 A(H1N1)pdm09 pandemic and therefore lacked pandemic-induced immunity. In addition, more than half those born after 2009 now attend school (i.e. 5–9-year-olds), a socio-behavioural context that may enhance transmission and did not apply during prior A(H1N1)pdm09 epidemics.

Jamaica: Three H1N1 deaths - Opposition raps government for failing to issue advisory on deadly flu

Thanks to Sean Smith for alerting me to this story. Via The Jamaica Gleaner: Three H1N1 deaths - Opposition raps Gov’t for failing to issue advisory on deadly flu. Excerpt:

The Ministry of Health has faced scathing criticism for failing to inform the public about the presence of the influenza H1N1 in the country, following yesterday’s revelation by broadcaster Alan Magnus that his late wife Karlene ‘Kerry’ Douglas died last Friday due to complications associated with the virus.  

“I have heard of several people dying from it. [For] Kerry’s death, the paper which we got from the hospital stated that that’s what she died from,” Magnus said while speaking on RJR 94 FM.  

Yesterday, Nicole Dawkins-Wright, acting director of emergency, disaster management and special services in the Ministry of Health, confirmed that three Jamaicans have died as a result of the H1N1 influenza virus in St Ann, Kingston, and St Catherine. It was also revealed that there were six confirmed and 110 suspected cases across the island since the start of the year.  

She also told The Gleaner that the H1N1 virus present in the island is not the swine flu strain.

Meanwhile, Sean Smith also tells me, Guyana is dealing with H1N1. Via INews Guyana: BREAKING NEWS: 1 dead, 8 suspected Swine Flu cases detected in Region 1.

The Guyanese Ministry of Public Health website doesn't have anything on flu, and I can't even access Jamaica's Ministry of Health.

Flu News Europe, week 12

Flu News Europe has published its week 12 (March 18-24) update. Excerpt:

• Of 45 countries reporting on geographic spread only 11, located in northern, southern, and western areas of the European Region, reported widespread activity. Specimens collected from individuals presenting with ILI or ARI to sentinel primary health care sites yielded an influenza virus positivity rate of 38%, similar to the rate of 39% in the previous week. 

• Of 45 countries reporting on intensity, 41 reported baseline or low intensity. No countries reported high intensity levels. 

• Influenza type A virus detections dominated with more A(H3N2) than A(H1N1)pdm09 viruses among sentinel and non-sentinel source specimens. Few influenza B viruses were detected. 

• Of the specimens from patients with severe acute respiratory infection (SARI) collected in week 12/2019 that were tested for influenza viruses, 21% were positive and almost all were type A. 

• Pooled data from 22 Member States and areas reporting to the EuroMOMO project indicated that the excess mortality observed in previous weeks has returned to normal levels.

Flu News Europe, week 10

Flu News Europe has published its week 10 (March 4-10) update. Excerpt:

• Influenza activity was widespread in the European Region. Specimens collected from individuals presenting with ILI or ARI to sentinel primary health care sites yielded an influenza virus positivity rate of 42.8%. 

• Influenza type A virus detections dominated with slightly more A(H1N1)pdm09 than A(H3N2) viruses. Very few influenza B viruses were detected. 

• 28.3% of specimens from patients with severe acute respiratory infection (SARI) collected in week 10/2019 tested positive for influenza virus, and almost all were type A. 

• Pooled data from 22 Member States and areas reporting to the EuroMOMO project indicated that the excess mortality observed in previous weeks continued to decline. Excess mortality was seen in persons aged 65 years and above and, to a lesser extent, in persons 15-64 years.

Co-circulation of influenza A(H1N1)pdm09 and influenza A(H3N2) viruses, WHO European Region, October 2018 to February 2019

Eurosurveillance has published Co-circulation of influenza A(H1N1)pdm09 and influenza A(H3N2) viruses, World Health Organization (WHO) European Region, October 2018 to February 2019. The abstract:

In the World Health Organization European Region, the 2018/19 influenza season started in week 49 2018, crossing 10% virus-positivity in sentinel surveillance specimens. At week 5 2019, activity remained elevated with positivity rates at 55%. Both A(H1N1)pdm09 and A(H3N2) viruses circulated widely and detection levels in primary care and hospital settings were similar to past seasons. Hospitalisation data may suggest an increased susceptibility to A(H1N1)pdm09 virus in older age groups.

Interim 2018/19 influenza vaccine effectiveness: Six European studies, October 2018 to January 2019

Eurosurveillance has published Interim 2018/19 influenza vaccine effectiveness: six European studies, October 2018 to January 2019. The abstract:

Influenza A(H1N1)pdm09 and A(H3N2) viruses both circulated in Europe in October 2018–January 2019. Interim results from six studies indicate that 2018/19 influenza vaccine effectiveness (VE) estimates among all ages in primary care was 32–43% against influenza A; higher against A(H1N1)pdm09 and lower against A(H3N2). Among hospitalised older adults, VE estimates were 34–38% against influenza A and slightly lower against A(H1N1)pdm09. Influenza vaccination is of continued benefit during the ongoing 2018/19 influenza season.

WHO: Recommended composition of influenza virus vaccines for use in the 2019-2020 northern hemisphere influenza season

WHO has published Recommended composition of influenza virus vaccines for use in the 2019-2020 northern hemisphere influenza season. From WHO's email:

The WHO Consultation and Information meeting on the Composition of Influenza Virus Vaccines for use in the 2019-2020 Northern Hemisphere Influenza Season has concluded today, 21 February 2018, in Beijing, with the recommendations on the composition of the influenza vaccines for the following influenza season.

The periodic replacement of viruses contained in influenza vaccines is necessary in order for the vaccines to be effective due to the constant evolving nature of influenza viruses, including those circulating and infecting humans.

Twice annually, WHO organizes consultations with an advisory group of experts to analyse influenza virus surveillance data generated by the WHO Global Influenza Surveillance and Response System (GISRS), and issues recommendations on the composition of the influenza vaccines for the following influenza season.

These recommendations are used by the national vaccine regulatory agencies and the pharmaceutical companies to develop, produce and license influenza vaccines.

It is recommended that quadrivalent vaccines for use in the 2019-2020 northern hemisphere influenza season contain the following:

• an A/Brisbane/02/2018 (H1N1)pdm09-like virus;
• an A(H3N2) virus to be announced on 21 March 2019*;
• a B/Colorado/06/2017-like virus (B/Victoria/2/87 lineage); and
• a B/Phuket/3073/2013-like virus (B/Yamagata/16/88 lineage).

It is recommended that the influenza B virus component of trivalent vaccines for use in the 2019-2020 northern hemisphere influenza season be a B/Colorado/06/2017-like virus of the B/Victoria/2/87-lineage.

* In light of recent changes in the proportions of genetically and antigenically diverse A(H3N2) viruses, the recommendation for the A(H3N2) component has been postponed.

Flu News Europe week 6 update

Via Flu News Europe:

Week 6/2019 (4 -10 February 2019) 

• Influenza activity is widespread in the European Region. Specimens collected from individuals presenting with ILI or ARI to sentinel primary health care sites yielded an influenza virus positivity rate of 53%, slightly lower than in the previous week (58%). 

• Influenza type A virus detections dominated with A(H1N1)pdm09 viruses and A(H3N2) viruses co-circulating. Very few influenza B viruses were detected. 

• 46% of specimens from patients hospitalized with severe acute repiratory infection (SARI) collected in week 6/2019 were positive for influenza virus, and all were type A. 

• Pooled data from 24 Member States and areas reporting to the EuroMOMO project indicated excess mortality mostly among elderly aged 65 years and above, but also in adults in the age group of 15-64 years. 

2018/19 season overview  

• Influenza activity in the European region, based on sentinel sampling, exceeded a positivity rate of 10% in week 49/2018 and has increased continuously into week 5/2019 after which it started to decrease. The positivity rate has exceeded 50% since week 3/2019. 

• Both influenza A virus subtypes are circulating widely, with co-circulation in some countries while others report dominance of either A(H1N1)pdm09 or A(H3N2) viruses.  

• Among hospitalized influenza virus-infected patients admitted to ICU wards, 40% of influenza A viruses were subtyped; of these 78% were A(H1N1)pdm09 virus. Among influenza virus-infected patients admitted to other wards, 28% of influenza A viruses were subtyped and 71% were A(H1N1)pdm09 virus. 

• Over 90% of influenza A viruses detected from SARI surveillance since week 40/2018 were subtyped and 81% were A(H1N1)pdm09 virus.  

• In general, current influenza vaccines tend to work better against influenza A(H1N1)pdm09 and influenza B viruses than against influenza A(H3N2) viruses and preliminary vaccine effectiveness estimates continue to support the use of vaccines. Early data suggests the vaccine are effective and estimates vary  depending on the population studied and the proportions of circulating influenza A virus subtypes (e.g., higher VE in children). See data from Canada, Finland, Hong Kong, Sweden, and the United States.  

• Circulating viruses remain susceptible to neuraminidase inhibitors supporting early initiation of treatment and prophylactic use according to national guidelines.

Flu News Europe, week 5

Via Flu News Europe, an excerpt from its week 5 (January 28-February 3) update:

• Influenza activity is widespread in the European Region and continues to increase. Samples collected from individuals presenting with ILI or ARI to sentinel primary health care sites yielded an influenza positivity rate of 54.7%. 

• Influenza type A virus detections dominated with A(H1N1)pdm09 viruses and A(H3N2) viruses co-circulating. Very few influenza B viruses were detected. 

• Over 50% of specimens from patients hospitalized with severe acute respiratory infection (SARI) collected in week 5/2019 were positive for influenza, and >99% were type A. 

• Pooled data from 22 Member States and areas reporting to the EuroMOMO project indicated excess mortality in a elderly populations overall. However, this result was driven by data from only a few countries.