25th January 1990 - Nature. Letters page
F. HOYLE N.C. WICKRAMASINGHE University of Wales, School of Mathematics, Senghenydd Road, Cardiff CF2 4AG, UK
SIR-Some years ago, Hope-Simpson (1) pointed out a remarkable coincidence between peaks in the sunspot curve , when solar activity is at a maximum, and the occurrence of influenza pandemics associated with antigenic shifts of the virus.
He pointed to five coincidences over the period 1919-1968 as shown in the figure below.
Using historical evidence on flu-like epidemics as summarized by Beveridge',
we extended the comparison before 1919 as shown.
The first column ignores the abnormally low sunspot maxima in the years 1816, 1883 and 1905, and the second column includes both "certain" and "possible" pandemics in the judgement of Beveridge'.
Although the correspondences between the figure and our table are clearly not precise, they do add credence to the speculation that s
Solar activity and influenza activity may have a causal link.
The two phenomena, which have irregular periods (with an average period of 11 years), appear to have kept in step over some 17 cycles. Past experience has shown that false correlations of phenomena with the sunspot cycle may look good over a few cycles but go seriously adrift after an appreciable number of cycles. This does not happen for the postulated sunspot-flu connection.
Following the broad sunspot peak in 1968-70, the next peak occurred in 1979-80 coinciding closely with the 'Red Flu' pandemic of 1978-79 (see figure).
The sunspot relative numbers from May to October 1989 are given as follows: 159, 166, 172, 176, 176, 175. The indications are that a peak has been reached in August/September 1989, and that this peak is the second highest on record .
The highest recorded sunspot peak which occurred in 1957 coincided with the Asian flu pandemic of 1957-58. It is tempting to connect the recent flu epidemic in Britain with a maximum or imminent maximum of solar activity.
The rise of sunspot numbers towards this peak is possibly amongst the steepest on record. Although the new wave of flu and flu-like illness has not yet assumed pandemic proportions, the chances of this happening within a single complete cycle of terrestrial seasons must be reckoned to be high.
In conclusion we note that electrical fields associated with intense solar winds can rapidly drive charged particles of the size of viruses down through the exposed upper atmosphere into the shelter of the lower atmosphere , the charging of such particles being due to the photoelectric effect.
This could define one possible causal link between influenza pandemics and solar activity.
F. HOYLE N.C. WICKRAMASINGHE
University of Wales
School of Mathematics
Senghenydd Road
Cardiff
CF2 4AG, UK
1. Hope-Simpson, R.E. Nature275, 86 (1978).
2. Beveridge, W.I.B. Influenza, the Last Great Plague (Heinemann, London, 1977).
3. Hoyle, F. & Wickramasinghe, N.C. Diseases from Space (Oent, London, 19 79)
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