— announced that early trial results indicate an effectiveness of their vaccine of over 90%. And that is very positive indeed. preliminary results of the phase 3 human trials
That's a fair question, and the answer is that not all humans have the same immune system. Vaccinology, just as most medical sciences, is not an exact science like mathematics. But what matters in this quest for a vaccine — what is crucial — is that they are well over 50% effective. The figures from Pfizer and Moderna, at first view, look better than for instance the flu vaccine .
The other way to achieve herd immunity is where everyone gets the virus, some may get sick or die, and the rest then develops antibodies. But that's seen as unethical because it leads to deaths and suffering, and overflowing hospitals. In addition, quite a few people who got infected in the first wave and developed antibodies, nevertheless got infected again during the second wave. Unfortunately, coronaviruses in general are known to induce only temporary immunity.
And that will be important, because if history and previous viruses are any guide, the toughest time is still ahead of us. With the Spanish Flu, and with many other viruses, most people got infected, and got sick or even died, during the winter season. For us, that highest risk season is now. . Together, they lead to near perfection. They are wearing a mask, keeping distance, ventilating the airflow, and reducing your time of interaction.
Peter, remember how I told you that it was OK to play football outdoors back in September, but that you needed to stay out of the locker room? That's because in the outdoors, any kind of particles evaporate in seconds, whereas they'll keep "hanging around" for hours in a small confined space with moreover many people in it. You can look at it another way too.
petervanham good luck