Hospital, ICU admissions reduced by early antiviral treatment for H1N1 in organ transplant recipients

Antiviral treatment administered at the onset of influenza symptoms reduced the risk for morbidity and mortality among solid organ transplant recipients, according to data from a multicenter study.

Researchers analyzed data for 237 adults (n=154) and children (n=83) who received organ transplants and contracted influenza A (H1N1) between April 2009 and December 2009. The study was designed to determine the effects of H1N1 and factors leading to severe disease — measured by admission to hospitals and ICUs — in transplant patients.

Median time from transplant to symptom onset was 3.6 years (14 days to 21.9 years). Seventy percent of patients were admitted to the hospital a median of 2 days after symptom onset, and 16% were admitted to the ICU a median of 5 days after symptom onset. Twenty-one of 37 patients admitted to the ICU needed mechanical ventilation for a median of 12 days.

Of the 230 patients for whom complication data were available, 32% had pneumonia and 4% died.

Antiviral treatment was used to treat 94% of patients and was more effective when administered within 48 hours of the onset of symptoms. Eight percent of those treated within 48 hours required admission to the ICU compared with 22% who were treated after 48 hours (P=.007). In addition, patients treated early had a lower incidence of hospital admission (P=.049) and need for mechanical ventilation (P=.019).

“Although a formal controlled study in immunocompromised individuals, such as transplant recipients, is still lacking, the results from this and other uncontrolled studies support the use of antiviral drugs in this population,” Per Ljungman, MD, PhD, professor at the Karolinska University Hospital in Stockholm, Sweden, wrote in an accompanying editorial.

According to Ljungman, existing studies among solid organ and stem cell transplant recipients suggest that vaccines are safe and that the benefits of vaccination outweigh the risks associated with influenza infection.

“The experiences from the 2009 pandemic should emphasize the importance of yearly influenza vaccination in these high-risk cohorts,” Ljungman wrote.

Kumar D. Lancet. 2010;doi:10.1016/S1473-3099(10)70133-X.

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