Antibody Treatment May Benefit Severely Ill H1N1 Patients
According to the CDC, the US Public Health Emergency for 2009 H1N1 Influenza expired on June 23, 2010 with the World Health Organization declaring an end to the global pandemic in August. Unfortunately, people do still become ill with the virus, including the recent tragic loss of singer Trish Keenan of the British band Broadcast.
Plasma Antibody Transfusion Resulted in Improved Patient Survival
Ms. Keenan died of complications from pneumonia after being hospitalized and critically ill with the H1N1 flu virus since Christmas. According to a report from the NY Daily News, Britain has been hit by a number of swine flu cases in recent weeks, with over 50 dying this winter alone.
The US Centers for Disease Control and Prevention recommend a yearly flu vaccination – this year’s version protects against the 2009 H1N1 virus as well as influenza – for everyone 6 months and older. But for those who can’t, or won’t, receive the vaccine and do fall ill with the swine flu, the treatment for the virus includes Tamiflu (oseltamivir) or Relenza (zanamivir).
Unfortunately, though, there are people who fail to respond to standard drugs.
Researchers from the University of Hong Kong, led by virologist Kwok-yung Yuen, have found that convalescent plasma antibodies obtained from survivors of the disease, respond well with decreased respiratory secretions and lower inflammatory parameters.
The team tested the treatment in a study involving a total of 93 patients with severe H1N1 infection between September 2009 and June 2010. All were offered the antibody treatment option, but only 20 accepted. The remainder was given the standard treatment.
The plasma was obtained by apheresis from patients who had recovered from H1N1 at least two weeks previously. The patients receiving the treatment were infused with 500 mL of plasma over a four-hour period on day 2 of the stay in the intensive care unit.
Twenty percent of those in the antibody group died compared to nearly 55% of those who did not receive the experimental therapy. None of the patients developed adverse events from the treatment.
"Most (severely ill patients) come to hospital very late, on day 5 or 7 (after onset of symptoms). Our experience has been that antiviral drugs don't work very well," said Yuen.
"One of the benefits of convalescent plasma treatment in patients with severe influenza A infection is that it does not suffer from the problem of drug resistance. Additionally, it would remain effective until the virus has changed significantly enough to affect immunity. This form of treatment may be useful in future novel viral infections."
Hung I, et al "Convalescent plasma treatment reduced mortality in patients with severe pandemic influenza A (H1N1) 2009 virus infection" Clin Infect Dis 2011; 52: 510-519.