For the past four days, Indonesian health authorities and WHO have been monitoring cases of influenza-like illness in four nurses who were involved in the care of confirmed H5N1 patients.

Test results have now convincingly ruled out H5N1 infection in all four nurses.

Two of the nurses cared for siblings, a 10-year-old girl and her 18-year-old brother, who were hospitalized in Bandung, West Java, on 22 May and died the following day. Test results for both nurses are negative for H5N1 infection. One nurse was shown to be infected with a seasonal influenza A (H1N1) virus, which is now circulating widely throughout Indonesia. The second nurse experienced only mild and transient symptoms, but was tested urgently as a precautionary measure. Her test results were also negative for H5N1 infection.

The two additional nurses, who work at a hospital in Medan, North Sumatra, were involved in the care of confirmed H5N1 cases among members of an extended family from the village of Kubu Simbelang in Karo District. One of the nurses, a 34-year-old woman, experienced only mild symptoms and has subsequently tested negative for H5N1 infection. The second nurse, a 42-year-old woman, developed influenza-like illness on 1 June. Test results received today are also negative for H5N1 infection.

The speed and thoroughness with which influenza-like illness in these nurses was investigated are indicative of the heightened concern among Indonesian health authorities. The negative test results for all four nurses provide reassuring evidence that the virus is not spreading efficiently or sustainably among humans at present.