News Scan for Jun 10, 2013

News brief

Study: Flu vaccine does not raise risk of non-flu respiratory virus infections

A study from a Wisconsin team indicates that influenza vaccination does not increase the risk of infection with other respiratory viruses, which supports the validity of a common method for assessing flu vaccine effectiveness (VE) in observational studies.

As the team explains in Clinical Infectious Diseases, the test-negative control study design involves recruiting patients who present for treatment of acute respiratory infections; those who test positive for flu are counted as cases, while those who test negative are controls.

It has been proposed that flu vaccination may increase the risk of non-flu respiratory infection by decreasing temporary nonspecific immunity. If so, the risk of non-flu infections would be higher in vaccinated than unvaccinated persons, and the control group would have a higher percentage of vaccinated people than the source population. In theory, this could lead to overestimates of VE.

To test this, the authors looked for 19 respiratory viruses in samples that had been collected in a Wisconsin cohort during flu VE studies from 2004-05 through 2009-10.

They found flu viruses in 12% of 2,010 children under age 5 and 20% of 1,738 adults 50 and older.

Viruses other than flu were found in 70% of the children and 38% of adults who did not have flu. The percentage who had had flu shots didn't differ between non-flu-virus–positive controls and "pan-negative" controls in children (P = .62) or adults (P = .33).

Flu infection was linked to reduced odds of vaccination, but odds ratios differed very little when the analysis used flu-negative or non-flu-virus–positive controls.
Jun 6 Clin Infect Dis abstract


Hepatitis A outbreak linked to berry mix rises to 87 cases

Twenty-six more people have been sickened in a hepatitis A outbreak linked to a frozen berry mix distributed by Oregon's Townsend Farms, raising the total to 87 so far, the US Centers for Disease Control and Prevention (CDC) said today. Cases have been reported from one more state, pushing that total to eight.

Based on an investigation of 68 patients, 36 (53%) were hospitalized. No deaths have been reported.

Forty-six of the sick people (70%) reported eating Townsend Farms Organic Antioxidant Blend frozen berry and pomegranate mix from Costco stores. However, the mix was also sold at Harris Teeter stores, and so far none of the cases has been linked to product bought at that supermarket chain.

Earlier this month Townsend Farms recalled its products due to potential contamination.

Analysis of samples from two states suggests the hepatitis A outbreak strain is genotype 1B, which is rarely seen in the Americas but circulates in North Africa and the Middle East. The berry blend contained ingredients that originated in the United States, Argentina, Chile, and Turkey.

The CDC said the disease typically is spread by infected food handlers, but food contaminated with hepatitis A can cause outbreaks in people who eat or handle the food.
Jun 10 CDC update
Jun 6 CIDRAP News scan "Berry-linked hepatitis A outbreak grows to 61 cases"


Texas woman arrested for allegedly mailing ricin-tainted letters

Police have arrested a Texas actress in connection with the mailing of ricin-containing letters to President Barack Obama, New York City Mayor Michael Bloomberg, and the director of an anti-gun group, NBC News reported Jun 7.

The woman, Shannon Rogers Guess Richardson, 35, of New Boston, Tex., originally told the FBI that her husband, Army veteran Nathaniel Richardson, sent the letters, officials said. Instead, investigators determined that she sent the letters herself, the story said. She has played minor roles in several TV shows.

The letters were all postmarked May 20 from Shreveport, La. Those sent to Obama and Bloomberg were detected during routine mail screenings, but the letter mailed to the director of Mayors Against Illegal Guns, Mark Glaze, was opened.

In an earlier case, J. Everett Dutschke, 41, of Tupelo, Miss., was arrested Apr 27 in connection with ricin-laced letters sent to Obama and two other officials.
Jun 7 NBC News story


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