There’s no getting around it — we all age, and as we age our health declines. This is due in part to the decline of the immune system, our primary protection against pathogens (viruses, bacteria) and even cancer cells, making us more susceptible to infection and diverse diseases. And as we age we respond less well to vaccinations and other preventive measures.
Why do these changes take place? The challenge mostly lies in understanding how cells in our body (including the ones that form the immune system) function, a highly complex process that is precisely orchestrated through regulatory mechanisms.