H5N1

Hong Kong enters winter influenza season

Via the Centre for Health Protection: Hong Kong enters winter influenza season.

The Centre for Health Protection (CHP) of the Department of Health today (January 10) announced that local seasonal influenza activity has continued to increase in the past week and exceeded the baseline level, indicating that Hong Kong has entered the 2017-18 winter influenza season. The community should heighten vigilance and maintain personal protection against influenza.        

The positive percentage of seasonal influenza viruses among respiratory specimens received by the CHP increased from 9.76 per cent in the week ending December 30 to over 15 per cent in the following week. The circulating influenza viruses in the past week were predominantly influenza B, with low influenza A activity.      

In the above period, the weekly average rate of the influenza-like illness (ILI) syndrome group in the accident and emergency departments increased from 195.3 cases per 1 000 coded cases to 208.8. The overall admission rate with principal diagnosis of influenza in public hospitals increased from 0.26 per 10 000 population to 0.40.        

After the Christmas and New Year holidays, the CHP recorded an increase in institutional ILI outbreaks from two (affecting six persons) in the week ending December 30 to five (affecting 21 persons) last week. In the first three days of this week, 13 ILI outbreaks (affecting 46 persons) have been recorded. The above outbreaks occurred in primary schools (eight), residential care homes for the elderly (five), kindergartens/child care centres (five), a residential care home for the disabled (one) and a hospital (one).        

The CHP has collaborated with public hospitals under the Hospital Authority and private hospitals to monitor influenza-associated admissions to intensive care units (ICU) and deaths among patients aged 18 years or above as routine surveillance throughout the year starting in 2018. As of yesterday (January 9), 24 cases (10 deaths) had been recorded. Of note, the causes of ICU admission or death among the cases may be due to other acute medical conditions or underlying diseases. 

Starting tomorrow (January 11), the weekly surveillance data on adult severe influenza cases will be reported in the CHP’s Flu Express published every Thursday.      

In children aged under 18, routine surveillance of severe influenza-associated complications or deaths is ongoing. As of yesterday, one case had been recorded this year. In 2015, 2016 and 2017, 25 (one death), 31 (four deaths) and 27 (four deaths) cases were recorded respectively. Among them, 73 cases (88 per cent) did not receive seasonal influenza vaccination for the respective season.

Flu News Europe, week 52

An excerpt from the latest Flu News Europe: 

Week 52/2017 (25–31 December 2017) 

• Influenza activity was increasing in countries in northern, southern and western Europe. 

• Both influenza type A and B viruses were co-circulating and mixed patterns of circulation were observed across the Region. 

• Of the individuals sampled, on presenting with ILI or ARI to sentinel primary healthcare sites, 44% tested positive for influenza viruses, an increase from 38% in the previous week. 

2017/18 season overview  

• An early risk assessment based on data from EU/EEA countries was published by ECDC on 20 December 2017. First detections indicated circulation of A(H3N2) and B/Yamagata viruses in the highest proportions. As the A(H3N2) subtype dominated last season, a high proportion of the population should be protected. 

• From sentinel sources, a higher proportion of type B viruses compared to type A viruses has been detected. Of the type A detections, A(H1N1)pdm09 viruses have outnumbered A(H3N2) viruses. 

• For type B viruses from both sentinel and non-sentinel sources, B/Yamagata lineage viruses have greatly outnumbered those of the B/Victoria lineage. 

• While low in number, 59% of the genetically characterized A(H3N2) viruses belonged to clade 3C.2a, the vaccine virus clade as described in the WHO recommendations for vaccine composition for the northern hemisphere 2017–18, and 40% to clade 3C.2a1, with viruses in both clades being antigenically similar. 

Other news 

• The US CDC published a Health Alert Network (HAN) notice, regarding increased A(H3N2) activity that affects mostly people aged over 65 and younger children, leading to more hospitalizations and deaths. Based on the moderate vaccine effectiveness, detailed information on recommended antiviral treatment is provided. See full report here. 

• Additional information on global influenza activity is available from WHO’s biweekly global updates.

Hong Kong: CHP appeals for heightened vigilance against increasing seasonal influenza activity

Via the Centre for Health Protection: CHP appeals for heightened vigilance against increasing seasonal influenza activity. Excerpt:

The Centre for Health Protection (CHP) of the Department of Health today (January 3) reported that local seasonal influenza activity has been increasing in the past two weeks, and appealed to the community for heightened vigilance as Hong Kong will enter the winter influenza season soon.        

"Our latest surveillance data show that the local seasonal influenza activity steadily increased from a baseline level. We anticipate that the seasonal influenza activity will continue to increase and the winter influenza season in Hong Kong will arrive soon. Members of the public should maintain good personal protection against influenza," a spokesman for the CHP said.        

"Particularly, children, the elderly and those with underlying illnesses are urged to get vaccinated as early as possible to prevent seasonal influenza as it takes about two weeks for antibodies to develop in the body after vaccination. They should promptly seek medical advice if influenza-like symptoms develop so that appropriate treatment can be initiated as early as possible to prevent potential complications. Parents and carers are reminded to render assistance in prevention, care and control for vulnerable people," the spokesman added.        

The positive percentage of seasonal influenza viruses among respiratory specimens received by the CHP increased from 3.93 per cent in the week ending December 16 to 6.02 per cent and 9.32 per cent in the following two weeks. The circulating influenza viruses in the past two weeks were predominantly influenza B, with low influenza A activity.        

In the above period, the weekly average rate of the influenza-like illness (ILI) syndrome group in the accident and emergency departments increased from 161.3 cases per 1 000 coded cases to 170.2 and 196.1. The overall admission rate with principal diagnosis of influenza in public hospitals increased from 0.09 per 10 000 population to 0.15 and 0.23.         

As of December 26, 2017, about 369 100 and 244 600 doses of seasonal influenza vaccines had been administered via the Government Vaccination Programme (free vaccination) and the Vaccination Subsidy Scheme (subsidised vaccination) respectively, increasing by 10.0 per cent and 3.4 per cent from the same period in the 2016-17 season.

CIDRAP: Flu rises sharply, now widespread in 36 states

Via CIDRAP, Lisa Schnirring writes: CDC: flu rises sharply, now widespread in 36 states. Excerpt:

Flu activity rose sharply last week, with 36 states now reporting widespread circulation and other markers such as clinic visits for flu and positive respiratory specimens also showing steep increases, the US Centers for Disease Control and Prevention (CDC) said today in its latest update. 

The new report underscores a warning that came from the CDC 2 days ago about steadily climbing flu dominated by H3N2, a subtype known for its heavy impact, especially on seniors and young children. Between that and known gaps in H3N2 protection in seasonal flu vaccines, the CDC also reminded providers that antiviral drugs are an important second line of defense in treating flu. 

Closer look at rising US flu markers 

In its report today, the CDC said since its last report, the number of states reporting widespread flu activity—encompassing a broad swath of the country—jumped from 23 to 36, and the proportion of respiratory samples testing positive for flu at clinical labs rose from 14% to 22.4%. 

Nationally, the percentage of clinic visits for flu—which climbed from 3.5% to 5%—has been at or above the national baseline for 5 weeks so far this season, the CDC said, adding that in recent seasons, flu has been at those levels for an average of 13 weeks.  

In its chart comparing clinic visits this year to the past five seasons, the pattern seems to be closely following the moderate-to-severe 2014-2015 season, which was also dominated by H3N2. 

High flulike illness activity, another marker of clinic visits for flu, was reported in 21 states, with regional activity reported by 13 states and Puerto Rico. 

Flu hospitalizations are rising steadily, and last week were at an overall rate of 8.7 hospitalizations per 100,000 population. The levels were much higher in seniors, at 35.8 per 100,000 population.

WHO: Influenza update, December 25

WHO has published Influenza update - 305. Excerpt from the summary:

Influenza activity continued to increase in the temperate zone of the northern hemisphere while in the temperate zone of the southern hemisphere activity decreased at inter-seasonal levels. In Central America and the Caribbean, influenza activity remained low. Worldwide, influenza A(H3N2) and B viruses accounted for the majority of influenza detections.  

• In North America, overall influenza activity continued to increase in the region, with detections of predominantly influenza A(H3N2) viruses. 

• In Europe, influenza activity continued to increase, but remained low in most of the countries, with detections of predominantly influenza B followed by influenza A(H3N2) viruses. 

• In Western Asia, elevated levels of influenza activity were reported in in recent weeks, with influenza A(H1N1)pdm09 predominantly detected. 

• In Central Asia, low to no influenza activity was reported. In East Asia, influenza activity remained low in most of the countries with the exception of China where influenza like illness (ILI) and influenza percentage positive continued to increase, with influenza B Yamagata-lineage viruses predominantly detected. 

• In South East Asia, low levels of influenza activity were reported. 

• In Southern Asia, influenza activity remained low in general. Detections of influenza A(H1N1)pdm09 and A(H3N2) viruses were reported in India and of all seasonal subtypes in the Islamic Republic of Iran.

Identifying factors that may improve mechanistic forecasting models for influenza

Via bioRxiv: Identifying factors that may improve mechanistic forecasting models for influenza. The abstract:

Influenza causes substantial morbidity and mortality and places strain on healthcare systems, some of which could be mitigated by accurate forecasting. Specific humidity and school vacations have both been shown independently to affect the transmission dynamics of influenza at large spatial scales. 

Here, we compare the ability of five compartmental transmission models, which include these two processes, to explain influenza-like-illness (ILI) incidence data for five United States counties for which school vacations and specific humidity data were available over a span of four seasons. We used the models in two different ways. 

First we fitted all available data at the same time and assessed model performance using standard measures of parsimony and goodness-of-fit. Then we conducted a retrospective forecasting study in which we attempted to predict incidence beyond a given week by fitting to data available up to that week. In general, when fitting the data using the whole season, we found that either specific humidity, school closures, or a combined model incorporating both effects captured the variability in incidence better than a fully constrained SIR-like model. 

Moreover, where these factors play a role, the timing of the variations suggests a causal relationship. When school vacations and specific humidity were important, the model-estimated parameters were broadly consistent. Retrospective forecasting simulations were consistent with the explanatory use of the models, with both specific humidity and school vacations giving more accurate forecasts than a simple SIR-like model in some populations and for some seasons. 

Our results suggest that influenza forecast models should test for the importance of different factors such as school vacations and specific humidity on a population-by-population and year-by-year basis.

Hong Kong: Influenza activity notably drops in consecutive weeks

Via the Centre for Health Protection: Influenza activity notably drops in consecutive weeks.

The Centre for Health Protection (CHP) of the Department of Health today (August 9) reported that the local seasonal influenza activity and influenza admissions to public hospitals continued to decrease in recent consecutive weeks.      

"Our latest surveillance data show that, after its peak in mid-July, the influenza activity has been on the decline as most parameters including laboratory surveillance, influenza-associated hospital admissions and institutional outbreaks have been decreasing in the past two to three weeks," a spokesman for the CHP said.      

The positive percentage of seasonal influenza viruses among respiratory specimens received by the CHP peaked at 40.86 per cent in the week of July 9 and further dropped from 35.52 to 25.28 per cent from the week of July 23 to that of July 30.      

In the same period, the number of institutional outbreaks of influenza-like illness substantially decreased from 39 (affecting 222 persons) to 15 (73 persons). As of yesterday (August 8), three (12 persons) had been recorded this week.

The average daily number of influenza cases admitted to public hospitals peaked at 350 per day in the seven-day period from July 11 to 17 and then steadily decreased to 135 per day recently (August 2 to 8).      

Regarding severe influenza cases, in adults, 474 cases of influenza-associated admission to the Intensive Care Unit or death (including 337 deaths) were recorded from May 5 to yesterday in the enhanced surveillance with the Hospital Authority and private hospitals, as compared with 647 cases (501 deaths) and 409 cases (211 deaths) recorded in the enhanced surveillance periods for the winter influenza seasons in 2015 and 2016 respectively.      

In children, in the same period, 19 cases of severe influenza-associated complication or death (three deaths) were detected. In 2017, there have been 27 cases (four deaths) so far.

The average daily number of severe cases among all ages peaked at 11.3 per day in the seven-day period from July 12 to 18 and then gradually decreased to 7.9 per day recently (August 2 to 8).

China: Tianjin reports a human H7N9 AIV case

Via Flu in China, a report from the Tianjin HFPC: China: Tianjin reported a human H7N9 AIV case.

Tianjin reported a human H7N9 AIV case on 13th April 2017. The 58-year-old female patient, surname Zhou, lived in Wuqing district of Tianjin city. 

She was admitted into designated hospital for severe pneumonia and her sample tested positive for H7N9 nucleic acid by Tianjin CDC. 

All close contacts of the patient are under close medical monitoring, no one has showed ILI symptoms so far.

Saudi Arabia: Predictors of MERS-CoV infection

Thanks to Greg Folkers for sending the link to this report in Travel Medicine and Infectious Disease: Predictors of MERS-CoV infection: A large case control study of patients presenting with ILI at a MERS-CoV referral hospital in Saudi Arabia. The summary:

Background 

A case control study to better characterize the clinical features, laboratory, and radiological abnormalities associated with MERS-CoV infection in order to help with early identification of this syndrome from other respiratory infections.  

Methods 

Eighty patients admitted to a hospital in Riyadh, diagnosed with MERS-CoV infection based on RT-PCR were matched on age, sex, and the presence of a co-morbid condition on a basis of 1:2 to other patients admitted with respiratory symptoms and tested negative for MERS-CoV on RT-PCR. 

Results 

None of the reported MERS-CoV presenting symptoms was significantly associated with being infected with MERS-CoV. On the other hand, WBC count was significantly lower in patients with confirmed MERS-CoV infection (median 5.7 vs 9.3, P: 0.0004). Neutrophil count was as well significantly lower in MERS-CoV patients (median 3.7 vs 6.7, P: 0.0001). Both AST, and ALT values were significantly higher in MERS-CoV infected group (AST median 42 vs 36, P: 0.03, and ALT median 33 vs 28, P: 0.003). 

Overall our MERS-CoV mortality rate was(10%) below the national figure of (40%). 

Conclusions 

None of the presenting symptoms are specific for MERS-CoV infection. And out of all the investigations WBC, neutrophil counts, AST and ALT values have some predictive utility.

ECDC: CDTR, week 6

ECDC has published Summary of public health threats, CDTR week 6/2016. Click or tap through to download the PDF and use the links. The summary:

The ECDC Communicable Disease Threats Report (CDTR) is a weekly bulletin for epidemiologists and health professionals about active public health threats. This issue covers the period from 7 to 13 February 2016 and includes updates on seasonal influenza and Zika virus infection outbreaks.   

Seasonal influenza 

Influenza transmission in Europe shows a clear seasonal pattern, with peak activity during winter months. Influenza A(H1N1)pdm09 viruses predominated, accounting for 87% of subtyped sentinel surveillance detections of influenza virus. An increase in cases of severe disease, mainly in people aged 15–64 years, was seen again this week, with most of them associated with A(H1N1)pdm09. 

During week 5, 25 of the 50 Member States and regions that reported epidemiological data from surveillance for influenza-like illness and acute respiratory infection indicated increasing rates. In the past week, countries also reported increasing numbers of cases of severe acute respiratory infection (SARI), as well as a high percentage of influenza-positive specimens.   

Thirty-eight countries reported influenza virus detections in specimens from sentinel sources, indicating increased influenza activity in the WHO European Region as a whole. Belarus, Greece and Ireland indicated high-intensity influenza activity; Finland, the Russian Federation and Ukraine reported very high activity, as in the previous week. ECDC monitors influenza activity in Europe during the winter season and publishes its report weekly on the Flu News Europe website.   

Zika - monitoring global outbreaks 

Since last week, no new additional countries or territories have reported laboratory-confirmed autochthonous transmission. As of 12 February 2016, 36 countries or territories have reported autochthonous cases of Zika virus infection in the past nine months. A case of congenital CNS malformation and microcephaly caused by transplacental Zika virus infections was reported by Slovenian scientists in The New England Journal of Medicine (NEJM) on 10 February 2016.  ECDC has published a scientific advance in reaction to this article.