together with HIV infections in adults
is the leading cause of death in Africa.
Tuberculosis is a deadly infectious disease caused by the tuberculosis bacteria
which affects the lung and other parts of the body. Most infections are
inactive and without any symptoms in the beginning but can progress to an
active tubercular disease which can be fatal if left untreated.
or acquired immune deficiency syndrome, as the
name suggests, is an infection caused by the virus HIV (human
immunodeficiency virus). The AIDS virus attacks
the body's immune system causing a breakdown of
the body's protective force. This can cause serious life-threatening opportunistic
HIV viruses infect the most important immune cells of
the body known as the white blood cells, with a special affinity for the T
helper cells. The T-helper lymphocytes
are responsible for fighting infections and maintaining the body immunity. The T-cells which have
a cluster of glycoproteins known as CD4 are specifically targeted and
eventually destroyed. As a rule, CD4 cell count decreases
as the HIV virus infection increases. A CD4 cell count helps doctors to determine the HIV infection
state of the patient and determines the treatment. The normal CD4 cell count ranges between 500-1500
cells per cubic millimeter of blood while a low count may depict AIDS.
Preventive therapy is imperative
to prevent the progression of inactive tuberculosis to an active case in
patients who are already immunocompromised with HIV infection. The developing and underdeveloped world is still
sadly lacking in the provision of preventive treatment for tuberculosis in
spite of the World Health Organization's strong recommendations. Routinely, isoniazid is given for six months to patients to
avert TB. However, most public health programs which resolve to avert the
symptomatic development of tuberculosis fail because of low completion rates,
re-infection of tuberculosis and drug resistance.
A recent comparative clinical study was conducted in
South Africa by Richard Chaisson, MD
and his associates from the Johns Hopkins Medical Institute in Baltimore, Maryland. This study was done to
observe three different new tuberculosis prevention treatments as apposed to
the standard regimen of isoniazid for a period of 6 months.
1148 adult patients with a positive tuberculin skin test without signs of active
tuberculosis were randomly selected.
These patients were at an
average age of 30 years and had a median CD4
cell count of 484 per cubic millimeter.
The aim of the study
was to assess whether the newer preventive treatment modalities can improve
these patients in comparison to isoniazid given alone for 6 months. These
patients were randomly divided into four groups where one group took rifapentine together with isoniazid once weekly for 12 weeks;
the second group was put on isoniazid and rifampin
twice weekly for 12 weeks; the third group was given continuous isoniazid daily
for about 6 years and the control group was put on a course of isoniazid daily for 6 months to
arrest the development of active tuberculosis. Every patient was also given pyridoxine with each dose of
antituberculosis medication and routine follow up was conducted to observe
their progress or the development of symptoms. All patients who developed
symptoms were examined with sputum smear, mycobacterial culture, and chest
who had received prior anti-tuberculosis treatment for more than 2 weeks, who
were under antiretroviral therapy given
for the treatment of HIV or who had a CD4 cell count of less than 200 per cubic
millimeter were excluded from the study.
of the study indicate that there was no remarkable difference in the incidence
of development of active tuberculosis or death between any of the three groups
treated with newer drug regimens and those taking isoniazid alone daily for 6
months (the control group). However, there
were grave unfavorable adverse effects observed with patients taking continuous
isoniazid daily for 6 years. Other serious adverse effects were also seen in
the groups with newer drug regimens but to a lesser extent. These
results show that these newer prophylactic or preventive medication regimens
against tuberculosis in a HIV infected adult or even the use of continuous
isoniazid for 6 years do not show better or more superior results compared to
those taking isoniazid alone for only 6 months.
New Regimens to
Prevent Tuberculosis in Adults with HIV Infection; Neil A. Martinson, M.B.,
B.Ch., M.P.H., Grace L. Barnes, B.S.N., M.P.H., Lawrence H. Moulton, Ph.D.,
Reginah Msandiwa, R.N., Harry Hausler, M.D., Ph.D., Malathi Ram, Ph.D., James
A. McIntyre, M.B., B.Ch., Glenda E. Gray, M.B., B.Ch., and Richard E. Chaisson,
M.D.; N Engl J Med 2011; 365:11-20.