Vaccine Response Impaired

The goal of this clinical trial is to examine immune responses to the BCG vaccine in healthy adults who have, or who have not, taken antibiotics to deplete their gut bacteria prior to vaccination. The main question it aims to answer is: does depletion of the gut microbiota lead to impaired BCG-induced protection against specific and non-specific to challenges to the immune system?

The goal of this clinical trial is to compare responses to Varicella Zoster vaccination between transplant patients on different medication regimens, and their healthy co-habitants. The main questions it aims to answer are: 1. Are there differences in vaccination immunological responses in transplant patients on different immunosuppression regimens? 2. Are there differences in vaccination immunological responses between transplant patients and their healthy co-habitants? Participants will all receive a 2-dose course of SHINGRIX recombinant Zoster vaccination, and have immunological responses measured and compared at 5 timepoints between 1 week to 1 year post-vaccination.

The current recommendation for a full course of measles-mumps-rubella-(varicella) vaccine (MMR(V)) is two doses. The problem is, many individuals within the vaccinated cohort show antibody levels that are below the level considered to be protective, even after two doses of vaccine. Because of these waning antibody levels, it is currently unknown whether highly vaccinated populations are protected from infection against measles, mumps, rubella, or varicella should they be exposed to any of these viruses. The uncertainty of a woman's immune status is partly due to the type of testing that is used to indicate protection. While immunity to viral infection requires both a humoral and a cell mediated immune (CMI) response, only humoral (antibody) responses are measured routinely in the laboratory. This study will examine CMI responses and the role of a third dose of vaccine for previously vaccinated women whose antibody levels are below the cut off. This study will not administer vaccine, but rather will include women who have received a third dose of vaccination through routine health care follow up in the study cohort.