HORITIENTÓW I D
LING
Poliomyelitis
Hid
FIGURE 4
MONTHLY MEASLES NOTIFICATIONS 1962 – MAY 1973
140
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122
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TEAR
63. Four cases of poliomyelitis were reported during the year as compared with two in 1971. Three of the cases were of the type 2 poliovirus infection, confirmed by laboratory investigation. The pro- gramme of vaccination consisted of giving one dose of type 1 polio- vaccine, soon after birth, followed by two doses of balanced trivalent vaccine at three and five months. Beginning in October 1971, a booster dose of the vaccine was introduced at the age of about 18 months.
64. Approximately 78 per cent of infants received one dose of type 1 polio-vaccine 3000 after birth, and 74 per cent of infants received two doses of the trivalent vaccine at maternal and child health centres. The annual general immunization campaign against poliomyelitis was held in January and March.
65. Virological investigation of the disease was maintained through- out the year. A poliomyelitis faecal survey among normal children
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aged under five was carried out in June-August, 'The result showed that the excretor rate of 'vaccine' types of poliovirus was 1.40 per cent, among a total of 501 children included in the survey. The 'wild' type of poliovirus (type 3) was detected in one child giving an excretor rate of 0.20 per cent. The findings of the survey indicated the con- tinuing existence of 'wild' poliovirus type 3 in the community, but did not demonstrate the existence of type 2 poliovirus which was isolated from three of the four cases of clinical poliomyelitis recorded during the year.
Influenza
66. The surveillance programme for influenza was continued on a year-round basis. Several general out-patient clinics have been des- ignated as influenza surveillance centres, and these reported regularly the number of influenza-like illnesses seen. The government virus unit continued to function as a World Health Organization National In- fluenza Centre during the year, and virological investigations of throat swabbings and throat washings were carried out routinely on samples taken from influenza-like cases. Deaths from influenza, pneumonia and bronchitis were recorded regularly as part of the programmes of epidemiological surveillance of the disease.
67. The disease occurred sporadically between January to May and August to October. The most prevalent strain of influenza A virus occurring in January to May was A/Hong Kong/5/72 while strain A/England/42/72 was most prevalent between August to October. Influenza virus B was isolated several times during the year. The strain B/HK/5/72 isolated in December is under close surveil- lance for possible epidemic spread in view of its significant change in antigenicity.
Telanus
68. This disease, although not notifiable, was recorded during the period under review with reasonable accuracy owing to the severity of the symptoms, requiring hospitalization of clinical cases. In past years, approximately half the cases reported were among the new-born whose births had not been attended by trained staff, and who had been ex- posed to various hazards from unsterile equipment. In 1972, tetanus Deonatorum was responsible for only 0.5 per cent of recorded cases, and infant mortality from such infection fell from 1.2 deaths per 1,000 in 1951 to 0.025 deaths in 1972.
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