Influenza in Melbourne, Australia, 1969

Discussion Papers-Session I Influenza in Melbourne, Australia, 1969 by A. A. FERRIS a Some information on Hong Kong influenza as seen in our unit in Melbourne during the Australian winter of 1969 is outlined below. This unit is an infectious diseases centre, rather like the National Communicable Disease Center in miniature, and it receives patients from a metropolitan population of over 2 million. Although the Hong Kong virus reached Australia in September 1968, we had no evidence of its pres- ence in Melbourne until February 1969, when several isolates were made from overseas travellers. No epide- mic occurreduntilthewinterand in mid-Junewe began to isolate virus. Most isolates were obtained during July, the peak of the epidemic occurred about 20 July, and the epidemic was over by mid-August. Over this 2-month period a diagnosis of influenza was virologically confirmed in 96 patients-in 84 patients by virus isolation with or without serological evidence and in 12 patients by serological evidence alone. Since we made no attempt to investigate " influenza " as diagnosed on clinical grounds by general practitioners, our data chiefly concern pa- tients with severe and complicated cases who came to the hospital, plus some members of the labora- tory and hospital staff who reported to staff clinics. This epidemic had 4 main points of interest, as follows: (1) Fewer hospital beds were required for patients with pneumonias, croup, etc. in 1969 when the Hong Kong virus was circulating than in the winter of 1968 when A2/Japan/68 was the epidemic virus. It also seems clear that there was less absenteeism in industry in 1969 than in 1968. (2) Of our 96 patients with proved influenza, 28 a Fairfield Hospital, Fairfield, Victoria, Australia. (about 29%) had received the currently available vaccine this year. Quite a lot of vaccine was used in the general population, but precise figures are diffi- cult to obtain. However, 40% of the volunteer blood bank donors aged 20-50 years, who are not a priority group for vaccination, had been vaccinated this year. (3) There were 6 deaths among our 96 patients. One of these patients, who was fully vaccinated, should perhaps be excluded-a 19-year-old girl who had Marfan's syndrome and died of a ruptured thoracic aorta. Another death was that of an elderly cardiac patient who was also fully vaccinated. The remaining 4 patients, who were all healthy middle- aged people and none of whom was vaccinated, died of classical influenza pneumonitis-large numbers of viruses in the lungs and no evidence of secondary infection. These were the only cases of this kind that I have seen. We had none at Fairfield in 1957, when those who died had secondary infection, mostly with antibiotic-resistant staphylococci. (4) In an attempt to explain the apparent anomaly of a few severe cases, some deaths attributable solely to influenza, and an over-all low morbidity, we examined a small sample (100) of non-vaccinated blood bank donors for neutralizing antibody. In a screening test using monkey kidney tissue, a 1: 4 dilution of serum, and 100 TCID50 of Hong Kong virus, we found antibody in 52% of the donors. This figure is reasonably close to the 45% we found by means of the same technique in a much larger sample of blood bank donors after the 1957 A2 epidemic. It is difficult to draw conclusions from our small sample this year, but perhaps there was quite a lot of very mild and subclinical Hong Kong influenza in Melbourne during the winter of 1969. 2381A Hong Kong Influenza in Madras State, India, 1968 by N. VEERARAGHAVAN a The Influenza Centre at the Pasteur Institute, Coonoor, was informed by the Port Health Officer, a Director, Government of India Influenza Centre, Pasteur Institute of Southern India, Coonor, India. Madras, that the ship S.S. Rajula with influenza on board was expected to reach Madras on 8 September 1968 from Singapore. When the ship arrived at Madras, 16 persons with suspected influenza were 2381B 399 -