Tuesday, August 31, 2010

‘vulnerable to influenza’

Michael Carter for Aidsmap (31 August 2010 )

Low CD4 cell count associated with poor response to swine flu vaccine for those with HIV

Many HIV-positive patients do not develop protective antibody levels after receiving the standard dose of the swine flu vaccine, a study published in the September 10th edition of AIDS shows. A low current CD4 cell count was the only factor associated with a poor response to the vaccine.

“The implications of this research are immediate for next year’s influenza vaccination campaign”, comment the investigators. “Our results suggest that if that vaccine is used at the currently recommended dose, a significant proportion of individuals will remain vulnerable to influenza”.

It is recommended that all HIV-positive patients should receive the seasonal flu vaccine. In 2009 the H1N1 (swine flu) virus was identified and the World Health Organization declared a global flu pandemic. A vaccine against the virus was developed and people with underlying health conditions – including HIV - were recommended to receive this.

Investigators from the University of Pennsylvania wished to see if the vaccine produced protective antibody levels in HIV-positive patients. The safety of the vaccine was also monitored.

“Up to 40% of HIV-positive individuals are not seroprotected after vaccination”, write the investigators.

“The presence of other underlying chronic diseases, medication use, poor nutrition, irreversible damage to the immune system and immunosenescence [decline of the immune system due to ageing], likely all play a role in decreased vaccine responsiveness in spite of successful treatment of the HIV infection”, they add.

A number of strategies are suggested by the researchers to enhance the response rate to the vaccination. These include the use of alternative vaccines; increasing the dose; the use of adjuvants; and the use of live vaccines.

The authors of an accompanying editorial note the findings of the study, emphasizing “suboptimal vaccine efficacy in HIV-infected persons represents a clinically important matter. Current evidence evaluating influenza vaccination efficacy in the HIV population remains insufficient”.

References

Poor immunogenicity of the H1N1 209 vaccine in well controlled HIV-infected individuals.
Tebas, Pablo; Frank, Ian; Lewis, Mark; Quinn, Joseph; Zifchak, Larisa; Thomas, Aleshia; Kenney, Thomas; Kappes, Rosemary; Wagner, Wayne; Maffei, Kathy; Sullivan, Kathleen; the Center for AIDS Research and Clinical Trials Unit of the University of Pennsylvania.
AIDS 24: 2187-2192, September 10, 2010. doi: 10.1097/QAD.0b013e32833c6d5c

Link to AIDS abstract

Editorial: Preventing influenza coinfection among HIV-infected persons: a complex picture coming into focus.
Reyes-Teran, Gustavo; Butera, Salvatore T
AIDS 24: 2283-85, , September 10, 2010. doi: 10.1097/QAD.0b013e32833dbcd2.

Link to AIDS editorial

Link to Aidsmap article

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