Flu Scan for Jan 07, 2014

New H7N9 case
;
Ethnic H7N9 protection differences
;
GBS and H1N1 vaccination

Guangdong province man hospitalized with H7N9

Another H7N9 case has been detected in China, the ninth such infection to be reported in Guangdong province, where several of the country’s recent infections have been found.

Hong Kong’s Centre for Health Protection (CHP) said in a statement that the patient is a 31-year-old man who lives in Shenzhen. He started having symptoms on Dec 30 and was hospitalized on Jan 3, where he is in stable condition.

The man has not had recent contact with poultry. The CHP said 35 of his close contacts were placed under medical surveillance, and so far no other H7N9 illnesses have been found.

The CHP noted, though, that it is following up on notification from Guangdong health officials that two of the contacts are Hong Kong residents, a 4-year-old girl and her 37-year-old mother who had traveled to Shenzhen from Dec 26 through Jan 6. The CHP’s contact tracing found that the girl has been asymptomatic and the mother came down with a sore throat yesterday. The girl and her mother have been isolated in the hospital, where their respiratory samples will be tested.

The man’s infection pushes the global number of H7N9 cases to 149.
Jan 7 CHP statement

In other developments, a telephone survey of Chinese citizens 2 weeks after the first H7N9 case was detected found a moderately high anxiety level, with a high level of trust in the government, according to a study published today in BMC Infectious Diseases. The researchers are from Shanghai and London.

The survey of 1,011 Shanghai respondents also found that people blamed the threat on hygiene levels, temperature changes, dead pigs floating in the Huangpu River, and recent migration to the city. They also said early news of the outbreak prompted them to buy preventive medicines.

Researchers said the findings suggest that the public values local expertise and transparency and that early anxiety about an outbreak can drive demand for certain products, potentially leading to shortages.
Jan 7 BMC Infect Dis abstract

 

Study hints at ethnic differences in cell-based H7N9 protection

Some ethnic groups, such as native people in Alaska and Australia, may be especially vulnerable to H7N9 infection, based on genetic factors that drive the cell-based response to flu viruses, an international research team based at the University of Melbourne reported yesterday in Proceedings of the National Academy of Sciences (PNAS).

People lack protective antibodies to the new virus, and several research teams are looking into the extent of cell-based protection. The PNAS study focused on how well cross-reactive CD8+ T lymphocytes (CTL) might protect against H7N9. When they compared the virus against other flu viruses, they found that 28% of the H7N9 peptides had the capacity to provoke a CTL response.

In the next part of the study, they examined blood cells from 52 healthy donors who had not been exposed to the H7N9 virus to estimate human leukocyte antigens (HLAs) that are able to present immunogenic influenza peptides to CTLs, which they estimated to range from 16% to 57% in the population.

The percentage varied by ethnicity, with some HLA alleles showing a robust CTL response against any influenza A virus, including H7N9. Other alleles that were more prevalent in indigenous Alaskan and Australian people showed a more limited CTL response.

The researchers noted that the findings were consistent with mortality during the 1918 pandemic and also reflected hospitalization and mortality patterns seen during the 2009 H1N1 pandemic. Although social and demographic factors likely played a role, genetic factors could have also played a role, they noted.

Clinical outcomes in Chinese patients infected with H7N9 could also be influenced by the level of cross-reactive CTL memory, the team wrote.
Jan 6 PNAS study

 

Study finds no rise in GBS with H1N1 vaccine in Europe

The risk of Guillain-Barre syndrome (GBS) was not elevated by pandemic 2009 H1N1 (pH1N1) vaccination in several European nations, a new PLoS One study found.

Researchers performed a self-controlled case series analysis on data from Denmark, Finland, France, the Netherlands, Norway, Sweden, and the United Kingdom during the 2009-10 pandemic. They identified 303 cases of GBS and Miller Fisher syndrome, a GBS variant. Of those, 99 were exposed to pH1N1 vaccines, most often adjuvanted Pandemrix and Focetria.

The unadjusted pooled relative incidence (RI) for pH1N1 vaccination and GBS was 3.5, based on all countries. This dropped to 2.0 after adjustment for month of the year and to 1.9 when the researchers accounted for contraindications.

In a subset involving only Dutch, Norwegian, and UK data, the team further adjusted for other confounders, which decreased the RI from 1.7 (adjusted for calendar month) to 1.4, which they report as the main finding.
Jan 3 PLoS One study

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