• Current news

21 July 2010 - Use of oseltamivir to limit household transmission of pandemic influenza

A study exploring the use of oseltamivir (Tamiflu) in preventing household transmission of pandemic H1N1 flu found that early treatment reduced the odds of secondary infection by 42%.   Of 362 Milwaukee households, 135 had information about oseltamivir use, and 25 reported early use of the drug.   The full paper can be found at: http://www.biomedcentral.com/1471-2334/10/211

21 July 2010 - WHO Weekly Update on oseltamivir resistant pandemic influenza (H1N1)

The WHO has published its latest weekly updates on the number of cases of oseltamivir resistant pandemic influenza A (H1N1).   The cumulative total cases in 302; all but one have the H275Y mutation and are assumed to remain sensitive to zanamivir.   The full summary can be found at: http://www.who.int/csr/disease/swineflu/oseltamivirresistant20100723.pdf

07 July 2010 - Study finds antivirals help reduce transmission

A study found that households using antiviral drugs for pandemic flu lowered overall transmission rates even though levels of adult-to-child transmission remained relatively high.   Dutch researchers studied 47 households early in the pandemic whose index case (the first sick member) and all household contacts took oseltamivir within 24 hours after detection of the index case.   They found a low secondary attack rate (0.075), but the attack rate from an adult to a child under 12 was 0.35.   The full paper can be found at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0011442

10 June 2010 - Study helps explain spread of drug resistance in seasonal H1N1

Scientists reporting in the journal Science (4th June) have identified a pair of secondary mutations that improved the 'fitness' of seasonal H1N1 viruses carrying the mutation that confers oseltamivir resistance.   The two mutations, called V234M and R222Q, were found in drug-resistant H1N1 viruses from the 2007-08 season.   These mutations restored the fitness of the H274Y viruses to the level seen in non-resistant viruses, and were found to have emerged before the resistance mutation became widespread suggesting that the oseltamivir resistance was enabled by 'permissive' mutations that allowed the virus to tolerate subsequent occurrences of H274Y.  The full paper can be found at: http://www.sciencemag.org/cgi/reprint/328/5983/1272.pdf

26 March 2010 - Researchers report peramivir-resistant H1N1 case

Researchers from the NIAID (National Institute of Allergy and Infectious Disease), USA have reported the development of oseltamivir and peramivir resistant influenza A (H1N1) infection.  Two immunocompromised patients developed resistance to oseltamivir after 14 days in one case, and nine days in the second case.  One of the patients whose condition deteriorated after 24 days treatment was treated with peramivir, which did not reduce viral shedding or improve the patient's condition.  The patient recovered after a 10-day course of zanamivir.  The full article can be found at: http://www.journals.uchicago.edu/doi/abs/10.1086/651605

26 February 2010 - Study shows that early oseltamivir treatment reduces H1N1 shedding

A study published in the journal Clinical Infectious Diseases has shown that patients receiving oseltamivir on days 1 to 3 of illness had significant shorter duration of viral shedding compared to those treated from day 4 onwards.  The study of 70 patients was undertaken during the containment phase response to pandemic influenza H1N1 in Singapore.  The full article can be found at: http://www.journals.uchicago.edu/doi/abs/10.1086/651083

22 February 2010 - Study shows that early oseltamivir treatment reduces H1N1 shedding

Researchers have found that a combination of the antiviral drugs amantadine, ribavirin and oseltamivir was effective against drug-resistant seasonal and novel H1N1 influenza.  In vitro testing showed "that the triple combination was highly synergistic against drug-resistant viruses, and the synergy of the triple combination was significantly greater than the synergy of any double combination."  The full article can be found at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009332?rss

16 February 2010 - Study shows that oseltamivir works well in very ill patients

A study published in the Canadian Medical Association Journal has shown that oseltamivir was well absorbed in critically ill patients in intensive care.  The study of 41 patients who needed ventilator support showed that a standard 75mg twice daily dose of oseltamivir achieved blood stream levels at concentrations in excess of those required to be effective against the virus.  The full article can be found at: http://www.cmaj.ca/cgi/content/abstract/cmaj.092127v1

05 February 2010 - Global tamiflu-resistant H1N1 cases reach 225

The WHO today reported that 225 cases of oseltamivir-resistant H1N1 have been detected worldwide to date.  Several clusters of person-to-person transmission have been observed, but these have not spead into the community.  All the isolates had the H275Y mutation that confers resistance to oseltamivir but not to the other neuraminidase inhibitor in general use, zanamivir (Relenza).  Of 142 cases for which data are available, 56 (40%) were severely immunocompromised, 54 (38%) were linked to treatment of flu, 16 (11%) were associated with preventative treatment and 16 did not involve any known antiviral use.  The full article can be found at: http://www.who.int/wer/2010/wer8506.pdf

02 February 2010 - French study shows some patients on antiviral therapy still test positive for influenza

In a letter published in the journal Emerging Infectious Diseases, a French study has shown that some patients with confirmed influenza A(H1N1) test positive after receiving treatment with oseltamivir.  Of 16 patients positive for H1N1, only 9 (56%) tested negative within 3 days of treatment with oseltamivir, while 3 (19%) still tested positive more than 5 days after treatment.  The authors conclude that the data raise questions about potential virus transmission during antiviral treatment, and the possible resistance of pandemic (H1N1) 2009 to oseltamivir.  The full article can be found at: http://www.cdc.gov/eid/content/16/2/351.htm?rss

13 January 2010 - Japan approves peramivir for the treatment of adults with influenza

Japan has approved peramivir, an intravenous neuraminidase inhibitor, for the treatment of adults with influenza.  Shionogi & Co Ltd has licensed the drug from the US-based BioCryst.  Japan is the first country to approve peramivir, although the US Food & Drug Administration (FDA) granted an emergency use authorisation in October 2009.  The full Shionogi statement can be found at: http://www.shionogi.co.jp/ir_en/news/detail/e_100113.pdf