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- Categorized in: December 2011
H5N1 Vaccine More Effective with DNA Primer
Response to the H5N1 avian influenza vaccine was enhanced when adult test subjects were primed with a DNA vaccine expressing a gene for a key H5N1 protein, according to research from the National Institute of Allergy and Infectious Diseases (NIAID).1
Volunteers who received the DNA vaccine 24 weeks before receiving a booster vaccine made from whole, inactivated H5N1 virus produced higher levels of antibodies that protect against influenza.
Developing an effective H5N1 vaccine has been difficult, because vaccines created from the whole, inactive virus have produced only modest amounts of antibodies.
“Our study was designed to test whether a gene-based DNA vaccine could prime the immune system and lead to a better antibody response following boosting with an inactivated H5N1 vaccine," said, Julie Ledgerwood, DO, co-lead author of the new report and the study's principal investigator. "We found that the DNA-primer vaccine improved the response to the inactivated H5N1 vaccine, but only when the boost interval was increased to 24 weeks."
Of the 26 volunteers who received the vaccines 24 weeks apart, 21 produced antibodies at levels researchers believed were high enough to protect them from the virus. Those levels were four times higher than the groups who received two doses of inactive virus vaccine with no DNA-primer vaccine. Of those volunteers who received the DNA prime four weeks before the flu vaccine, only 4 out of 15 produced protective levels of antibodies.
The research team is planning a larger trial looking at the effectiveness of a DNA primer to help improve antibody creation for seasonal influenza.
1: Lidgerwood JE, Wei CJ, Hu Z, Gordon IJ, Enama ME, Hendel CS, McTamney PM, Pearce MB, Yassine HM, Boynton JC, Bailer R, Tumpey TM, Koup RA, Mascola JR, Nobel GJ, Graham BS; the VRC 306 Study Team. DNA priming and influenza vaccine immunogenicity: two phase 1 open label randomised clinical trials. Lancet Infect Dis. 2011 Oct 3. [Epub ahead of print] PubMed PMID: 21975270.
Adherence to HCV Therapy Increases Virologic Response, Falters Over Time
Adherence to hepatitis C virus (HCV) therapy is directly related to an early and sustained virologic response, but that adherence falters over time, according to researchers at Perelman School of Medicine at the University of Pennsylvania, Philadelphia.1
Looking at data from the VA’s HCV clinical-case registry, researchers showed that early-virologic response increased with higher levels of adherence to ribavirin therapy over the initial 12 weeks of treatment.
However, the researchers saw a pattern found in many chronic disease treatment programs. Adherence dropped over time — between 3% and 6% for every 12-week interval. This kind of drop is especially seen in treatments that require a large number of pills daily. The newer varieties of antiviral drugs call for pills to be taken every eight hours, creating “pill-fatigue” among patients, the researchers said.
One way to counteract poor adherence could be to address side-effects from HCV drugs. Patients who received treatment for thyroid dysfunction, anemia or low white-blood-cell count had a higher adherence to antiviral therapy.
The study was funded by NIH, VA and the Agency for Healthcare Research and Quality.
1: Lo Re V 3rd, Teal V, Locale AR, Amorosa VK, Kaplan DE, Gross R. Relationship between adherence to hepatitis C virus therapy and virologic outcomes: a cohort study. Ann Intern Med. 2011 Sep 20;155(6):353-60. PubMed PMID: 21930852.
Organizational Culture Impacts MRSA Prevention
The culture of an individual hospital is key in implementing measures designed to prevent methicillin-resistant Staphylococcus aureus (MRSA), according to VA researchers. 1
Cross-sectional surveys were distributed to 16 medical centers assessing organizational culture and knowledge, attitudes and prevention practices. The final sample included 2,314 surveys (43% completed by nurses, 9% by physicians, and 48% by other healthcare personnel).
After analyzing the surveys, researchers found three factors account for the majority of prevention variance between facilities — staff engagement, hospital leadership and the amount of stress and feelings of being overwhelmed. Higher hospital leadership scores were associated with better hand hygiene, fewer reported barriers and more positive attitudes among staff. High levels of stress were associated with poorer prevention practices, more barriers and more negative attitudes.
These factors seemed to have greater impact on nurses and nonphysician healthcare personnel, the study found.
The researchers concluded that, in the future, when creating a prevention program, VA should focus not only on how organizational culture can impact a program, but create programs that target specific healthcare personnel in different ways.
1: Sinkowitz-Cochran RL, Burkitt KH, Cuerdon T, Harrison C, Gao S, Scott Obrosky D, Jain R, Fine MJ, Jernigan JA. The associations between organizational culture and knowledge, attitudes, and practices in a multicenter Veterans Affairs quality improvement initiative to prevent methicillin-resistant Staphylococcus aureus. Am J Infect Control. 2011 Aug 22. [Epub ahead of print] PubMed PMID: 21864944.