Study suggests high-dose flu vaccine beats standard dose in elderly
A study based on data from more than 2 million Medicare beneficiaries suggests that the high-dose influenza vaccine works better than a standard-dose vaccine for preventing probable flu illness and flu-related hospital admissions in elderly people.
The study, published online yesterday by The Lancet Infectious Diseases, was funded by the US Food and Drug Administration and included authors from that agency as well as from the Center for Medicare and Medicaid Services, and the Centers for Disease Control and Prevention.
The team identified Medicare beneficiaries 65 years and older who received high-dose or standard-dose inactivated flu vaccines from community pharmacies that offered both vaccines during the 2012-13 flu season. Sanofi Pasteur's high-dose vaccine contains four times as much antigen as standard-dose vaccines.
Outcomes were defined with billing codes on Medicare claims. The main outcome was probable flu infection as defined by receipt of a rapid flu test followed by dispensing of oseltamivir (Tamiflu). The secondary outcome was a hospital or emergency department visit with a billing code for influenza.
The authors compared outcomes during periods of high flu activity between Aug 1, 2012, and Jan 31, 2013. They identified 929,730 patients who received the high-dose vaccine and 1,615,545 recipients of standard-dose vaccines. The groups were similar in age and prevalence of underlying medical conditions.
Probable flu cases were 22% fewer (95% confidence interval [CI], 15%-29%) in the high-dose group than in the standard-dose group, with 1.01 cases versus 1.30 cases per 10,000 person-weeks, the report says. Likewise, the high-dose vaccine appeared to be 22% more effective (CI, 16%-27%) for preventing flu-related hospital admissions: 0.86 versus 1.10 admissions per 10,000 person-weeks.
The authors said that with the large population involved, the study is the first to show a significant reduction in flu-related hospitalizations in high-dose vaccinees. "These results provide important new information to be considered by policy makers recommending influenza vaccinations for elderly people," they write.
In an accompanying commentary, Eelko Hak, PhD, of the University of Groningen in the Netherlands commends the authors for their methods but comments that "unmeasured confounders such as smoking, functional status, alcohol drinking, or previous vaccine history could have been differentially distributed" between the high-dose and standard-dose groups, possibly biasing the results.
But he calls the estimated 22% advantage of the high-dose vaccine "certainly important," given the "suboptimal effectiveness" of flu vaccines in general.
Lancet Infect Dis abstract
Lancet Infect Dis commentary introduction
Canada confirms high-path H5N1 in British Columbia chicken coop
Authorities confirmed the presence of highly pathogenic H5N1avian flu on a noncommercial farm in British Columbia's Fraser Valley, according to a Feb 7 Canadian Food Inspection Agency (CFIA) report.
The outbreak occurred in a backyard coop that housed 80 chickens in the town of Chilliwack, the Canadian Press said on Feb 7. The farm is currently quarantined, all 80 chickens were culled, and authorities have instituted a 1-kilometer surveillance zone around the farm.
This is the first time H5N1 has been detected in British Columbia, which recently experienced numerous outbreaks of H5N2 avian flu on commercial farms and in a backyard coop. Canadian authorities said that they will use the same disease control measures to prevent the spread of both strains in domestic birds.
The report from Canada comes after H5N1 was discovered in wild birds in Washington state several weeks ago.
The virus confirmed in Washington and British Columbia is not the same strain as the H5N1 avian flu affecting birds and people in Asia and Egypt. The strain identified in North America poses no risk to people, although international trade restrictions remain in place.
Feb 7 CFIA report
Feb 7 Canadian Press story
Jan 21 CIDRAP News story on H5N1 in Washington state
At least 4 H5N1 cases reported in Egypt
At least four, and probably five, new cases of H5N1 avian influenza have been reported in Egypt, according to media reports yesterday, continuing a pickup in cases there this year.
An article yesterday from Al-Ahram, the country's largest news organization, says Egypt's health ministry identified four new confirmed cases, each in a separate location and each requiring hospitalization.
FluTrackers, an infectious disease news message board, posted an apparently machine-translated article giving more details on the case-patients; they are a 44-year-old man from Sohag governorate, a 2-year-old child from Alexandria, a 1-year-old girl from Giza governorate, and a woman of unspecified age from Cairo governorate.
The Al-Ahram report states further that "another three people were completely cured." However, FluTrackers, which keeps a running case list, says one of these, a 3-year-old child from Assiut, has not been reported on previously, which would indicate five rather than four new cases. The other two recoveries are in a 13-year-old girl from Qena governorate and a 19-year-old student from Beheira governorate whose cases were reported Feb 2 and 3, respectively.
Egypt, which had 11 deaths from avian flu in 2014, has seen 6 fatal cases already this year, the most recent reported Jan 21, according to Al-Ahram. FluTrackers notes 16 deaths in the country thus far in 2015.
Feb 8 Ahram Online article
Feb 8 FluTrackers post
FluTrackers case listing
China's Guangdong province reports more H7N9 cases
Chinese authorities confirmed this weekend that three people have been infected with H7N9 avian flu in Guangdong province.
Hong Kong's Centre for Health Protection (CHP) said a 73-year-old man from the city of Zhongshan and a 56-year-old man from the city of Jiangmen were diagnosed with H7N9 and are hospitalized in critical condition. A 52-year-old man from the Shenzhen was also confirmed as infected with H7N9 and is in stable condition, the CHP said.
Chinese news agency Xinhua reported the new cases today, saying that a total of 42 H7N9 avian flu cases have been reported in Guangdong this year. Provincial authorities have culled thousands of chickens and restricted the movement of poultry within the region.
The World Health Organization (WHO) yesterday confirmed 83 H7N9 cases in China, most of which had been previously reported by the CHP and mainland authorities. The 83 patients had symptom onsets from Dec 20, 2014, to Jan 27, 2015; 19 deaths occurred, and 93% of case-patients had exposure to poultry, the WHO said.
A total of 571 cases of H7N9 have occurred on the Chinese mainland since early 2013, according to FluTrackers, an infectious disease news message board.
Feb 9 Xinhua story
Feb 8 CHP statement
Feb 7 CHP statement
Feb 8 WHO update
FluTrackers H7N9 case list