[Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] A particularly nice report from S Africa in mid 20th century even measured the duration in a large number of ppl by following their TB skin tests and found a good number of them did not regain their immune memory back for at least a year (longest they looked).