@ralfie Going out on a limb here. While there have been people who look to vaccines, and specifically COVID, as starting or creating various health conditions, I see it from a different angle. A vaccine of any type creates an immune response in our system. Our bodies remain a mystery in many aspects, even after all this time and research. Receiving any vaccine is simply triggering our individual immune response, and that response may vary among different individuals, given our unique health status.

When we have lessening kidney function, it is standard protocol to track down and treat the underlying cause in order to mitigate the decline, and also treat the decline as much as possible. If you have not yet, perhaps speaking with your pharmacist to review your medications, both over-the-counter and prescribed, to make sure there are not unwanted interactions, will be a good step. Rule out whatever you can to figure out the decrease in function. A complete set of blood work, perhaps even a thorough physical exam. We have to advocate for ourselves a lot of the time.
Ginger