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and a committee of clinicians and pathologists investigated fully all cases notified as poliomyelitis which occurred thereafter to ensure that the causative strain was not related to the vaccine virus.

112. The second phase started on the first of March and was again continued for 10 days with an extension to the end of the month for the rural village communities.

113. During these two phases a total of 389,992 children received the oral vaccine which represents 66% of the child population aged 5 years and under.

114. Notifications of poliomyelitis fell sharply after the first feeding of the oral vaccine and during February and March only 13 and 4 cases respectively were reported.

115. This vaccination campaign had been planned some six months ahead to take place early in 1963, during the months of minimal cir- culation of the entero-viruses as gauged by surveys carried out during the two previous years. It seems certain that there was a change in the epidemiology and that a most unexpected outbreak of poliomyelitis due to Type II and Type III strains was halted by the oral vaccination campaign. The results of the campaign are now being assessed and it is hoped to publish a paper in the scientific press later in 1963.

116. In order to assess the antibody response to the vaccine, blood specimens were taken before vaccination from 194 children. Of these, 79 with no polio-antibodies were selected for follow up, all being in the age group 6 to 12 months. Rectal swabs were taken from the children prior to the feeding of the vaccine and out of 71 tested only 2 were positive for poliovirus. The overall percentage of triple negatives for polio antibodies in the age group 6 to 12 months was 40.5% and the most susceptible age group was below 9 months. Conversion rates were very satisfactory for Type II (98.5%) and Type III (95%) but for Type I the rate was only 66%, which may have been due to interference by other viruses at a time of year when the enterovirus carrier rate is known to be rising.

117. These same children were further investigated to ascertain the establishment of the vaccine in the intestinal tract. The average duration of excretion of vaccine poliovirus after feeding was found to be about 4 to 5 weeks. In general Type II was dominant and grew first in most of the children, followed by Type III. In the majority of these children Type I poliovirus appeared after the second feeding of vaccine. This is in accordance with previous world experience.

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Ophthalmia Neonatorum

118. 310 cases were reported as compared with 250 in 1961.

Puerperal Fever

119. Two cases, both fatal, were again recorded during the year and both occurred following delivery in the home without the help of a doctor or a qualified midwife.

Scarlet Fever

120. Sporadic cases occurred throughout the year. 19 cases were reported as against 29 in 1961.

Whooping Cough

121, 98 cases with no deaths were notified as against 47 with I death in the previous year.

OTHER COMMUNICABLE DISEASES WHICH ARE NOT NOTIFIABLE

Influenza

122. The notification of influenza is entirely voluntary. Cases reported during the year numbered 6,374 with 39 deaths compared with 6,223 and 39 in 1961. The A2/57 (A/Asian 57) strain was active during the year as indicated by twelve isulates obtained at intervals from throat washings.

Teranus

123. There were 139 cases notified during the year of which 82 occurred in new-born infants, mostly among those delivered at home, in villages situated in the New Territories. In such cases, assistance by an untrained person, the use of unsterile material and instruments and the common practice of applying raw ground ginger root to the umbilicus as a styptic combine to give a grave risk of tetanus neonatortim. Children attending Maternal and Child Health Centres are given routine immuniza- tion against tetanus using the toxoid preparations. The health education of parents and others in the areas most affected is a slow process. despite the very considerable efforts of the health staff of the New Territories.

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