Читать книгу Viruses: More Friends Than Foes (Revised Edition) - Karin Moelling - Страница 10

If there are new outbreaks, virologists or politicians have two possibilities: either to look into the history of virus epidemics or to look at other countries where the disease has progressed already — for CoV-2 that was China. Yet the virus was also new there. So the Influenza pandemic of 1918, the “Spanish Flu”, was studied carefully as potential model. The Spanish flu took off under extremely poor living conditions, crowded battlefields, a cold winter, poor sanitary conditions and famine. It cost the lives of 50–100 million people. It came in three peaks: the summer terminated the first peak and the Influenza disappeared, but it returned with the onset of winter, and this second wave surpassed the first one by far. A third wave came later and was again weak. This is the pattern which is in everybody’s mind now — the first wave may be over, but is there a much more dangerous second one still to come? Is this a valid model for COVID-19? That is the fear. We do not know. Also, we do not know whether CoV-2 is sensitive to summer temperatures like other respiratory viruses. During the northern summer, influenza viruses spread in the southern hemisphere, as it is winter there. Some CoV-2 has arrived there with some hot-spots of infection. Yet, the living conditions during the Spanish flu were poor and with present precautions we may prevent a second peak or face a weak one next winter.

Models have been published about the course of the epidemic in an article in the National Geographic (March 2020), in which the course of the Influenza epidemic of 1918 was shown for several US cities. An important piece of information was that a “flattened” curve of infection rates is likely to induce a second wave, and that the ending of the shut-down, the “exit strategy”, is important for the duration of the pause and for the height of the second peak. This is the basis for predictions. There are even models that predict many waves, depending on the alternation of stricture and relaxation. With all the measures taken against CoV-2 we may counteract a second peak.