- severe immunosuppression like hiv (human immunodeficiency virus) - long term use of immunosuppressant for any other chronic illness - pregnant or lactating females - patients who are on chronic use of corticosteroids like asthma, rheumatoid arthritis.

- severe immunosuppression like hiv (human immunodeficiency virus) - long term use of immunosuppressant for any other chronic illness - pregnant or lactating females - patients who are on chronic use of corticosteroids like asthma, rheumatoid arthritis.