There are at least four coronaviruses that cause the common cold. And immunity lasts only 6-12 months. So, this would be 4-8 vaccinations per year, for life, to

There are at least four coronaviruses that cause the common cold. And immunity lasts only 6-12 months. So, this would be 4-8 vaccinations per year, for life, to reduce colds by 20%. I might do that myself, but I’m not sure it would sell well enough to fund the costs of developing the vaccine.