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improbable that the use of vaccine containing tetanus toxoid added to one
or both of the others will become accepted practice.
Influenza
Influenza as such is not notifiable though influenzal pneumonia is.
The numbers of these, however, do not give any real idea of the prevalence
in influenza, because in most outbreaks only a small proportion of the
sufferers develop pneumonia.
In the earlier weeks of the year, which is the commonest time for
influenza to be present, the only notable outbreaks in the country as a
whole were in the service units, some at least of them due to Virus A.
There was little of it in this district and only one person here died from
influenza at this time of the year. This district was invaded, as was the
rest of the country, by the Asian influenza later in the year.
1957 Influenza Pandemic. This outbreak started in China in the
early spring, the virus being first isolated in March. The spread in the
subsequent months was very rapid, the complaint reaching Australia in
May. By July it had reached South Africa and Chile, and during August
was spreading in the Argentine, South Brazil and New Zealand, by which
time it had appeared in every continent. The northern counties of this
country were attacked early in August, and by the end of the month the
midlands were involved. By September those in the southern counties
were affected by a similar complaint. The peak incidence, as reflected by
new claims for sickness benefit was reached in Yorkshire by September
24th, north and north-western regions and Wales by October 1st, the
Midlands by October 8th, London and the southern, eastern and southwest
regions by October 15th.
The entry to countries was largely the result of cases having developed
in persons on ships, those in ports being first attacked and then those in
adjoining districts.
The organism, which has been designated as A/Asian/57, although
belonging to the A virus group, is the most aberrant type reported since
the discovery of the influenza virus in 1933. Antigenic variants of the
A virus have appeared in previous outbreaks, but in recent years these
variations have been fairly slight. Since most of the population have
never been in contact with this particular strain, they have not acquired
immunity to it, and this probably is the explanation of the rapidity of the
spread of this outbreak.
There were two features which distinguished this outbreak of
influenza from previous attacks. One was this very great invasiveness,
the illness affecting more particularly those in closed or semi-closed communities
such as schools and service establishments. The attack rate
ranged from 10 to 30 per cent, of those exposed, possibly 25 per cent.
for the country as a whole, a much higher rate than the 5 to 10 per cent.
for the attacks in 1951, 1953 and 1955. Children of ages 5 to 10 were
most affected, and teenagers. The other feature was the relatively mild
clinical type with low rate of complications. Although in general clinical
manifestations were mild, many patients suffered from pneumonia, a
proportion of these cases proving fatal. Possibly 5,000 persons died of
it one death to every 2,000 or 3,000 cases. Those attacked in this way