The success of HAART at reducing illness and death causes by AIDS-defining opportunistic infections is well documented. Now, a study conducted in the USA suggests that effective anti-HIV therapy has also reduced the number of hospitalisations and deaths in HIV-positive people caused by annual influenza epidemics.
Writing in the November 1st edition of the Journal of Acquired Immune Deficiency Syndromes American investigators describe a retrospective study which looked at rates of hospitalisation and death caused by pneumonia, influenza, respiratory problems and heart failure amongst HIV-positive individuals aged 15 - 50 receiving Medicaid during the influenza season (November - January) between 1995 and 1999.
The patients included in the study contributed 7,368 person-years of follow-up. As expected, the proportion of individuals receiving HAART increased significantly from 0.1% in 1995- 96, to 52% in 1998-99. This was accompanied by a significant overall drop in hospitalisations from 45% in 1995-96 to 26% in 1998-99.
When the investigators looked specifically at cardiopulmonary hospitalisations and deaths they found 313 instances of hospitalisation per 1,000 patient years and 220 deaths per 1,000 patient years pre-HAART in 1995. Hospitalisation rates fell by 48% the year after with the introduction of HAART falling by a further 5% per year with hospitalisation rates in 1998-99 135 per 1000 patient years with an all cause mortality rate of 50 per 1000 patient years.
Before the availability of HAART, the investigators estimated that 48 hospitalisations per 1,000 were due to influenza. This fell to five per 1,000 after the introduction of HAART, similar to that seen in other high-risk populations, and the investigators could find no deaths in the HAART era where influenza was the probable cause.
However, the investigators caution that HIV-positive patients, even if they are receiving successful treatment with HAART, should be considered for annual influenza vaccinations. They highlighted studies showing that the use of influenza vaccine does not have a sustained adverse effect on viral load or disease progression, and that the use of influenza vaccine was able to reduce by 65% the incidence of influenza amongst HIV-positive individuals in a residential facility.
Further information on this website
Preventing infections - factsheet
Neuzil K et al. Cardiopulmonary hospitalizations during influenza season in adults and adolescents with advanced HIV infection. JAIDS 34: 304 - 307, 2003.
Staprans SJ et al. Activation of virus replication after vaccination in HIV-1 infected individuals. Journal of Experimental Medicine 182: 1727 - 1737, 1995.
Tasker SA et al. Efficacy of influenza vaccination in HIV-infected persons. A randomized, double-blind, placebo controlled trial. Annals of Internal Medicine 131: 430 - 33, 1999.
Fine AD et al. Influenza A among patients with HIV: an outbreak of infection at a residential facility in New York City. Clinical Infectious Diseases 32: 1794 - 91, 2001.