Feb 5, 2010 (CIDRAP News) – The World Health Organization (WHO) reported today that 225 cases of H1N1 flu with resistance to oseltamivir (Tamiflu) have been found worldwide, and resistant viruses have spread from person to person in several clusters but have not spilled into the community.
Many of the resistant cases involved people with severely weakened immunity, reinforcing the importance of monitoring for the problem in such patients, the WHO said in today's issue of its Weekly Epidemiological Record.
The 225 cases come from 20 countries and include 65 cases in the Americas, 77 in Europe, 1 in Africa, and 82 in the Western Pacific region, the agency said. 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 were available, 56 (40%) were in severely immunocompromised patients, and 54 (38%) were linked to treatment of flu. Another 16 cases (11%) were associated with preventive treatment, and 16 others did not involve any known antiviral use.
If there are this many, then there are definately a lot more cases.