World over 30 - 40 million people are expected to be infected with HIV. 20 - 30% of them are women and 10 - 15% children. Sub - Saharan African countries account for the maximum number of cases and contribute 60 - 70% of total cases in world. Next is Asian sub - continent which contributes 5 - 6 million cases of which 80% are in India alone.

In India the official figures quoted in 1999 were 0.3 million HIV infected people and 68,000 cases of AIDS. Unofficially it is estimated that 4 - 5 million people are infected with HIV in India. Studies have shown the seroprevalence to be 1 - 2% in non - professional walk - in donors in some reputed blood banks in Mumbai and 1.8 - 4% in pregnant ladies attending antenatal clinics of some major general hospitals of Mumbai catering to non - high risk population. All this appears to be the reflection of prevalence in general population estimated to be 0.5%. The prevalence of HIV infection in commercial sex workers in Mumbai has risen from 55%in 1998 to 85% in 1999. There are estimated 0.1 million female sex workers (FWS) working in the established areas for such activities in Mumbai.

It is estimated that almost 10,000 people will die of HIV every day in India by next 10 - 15 years. Equal number of children will become destitute, as they would lose either one or both parents. We will need 6 times more beds to treat these HIV infected people. World over HIV threatens to kill more than 30 - 40 million infected people. At present one person dies of HIV every 3 - 4 minutes world over!

How does immunodeficiency occur?


HIV infects and destroys CD4+ T cells. CD4+ T cells or T helper cells help stimulation of B cells & conversion of B cells to plasma cells which produce specific antibodies and it also stimulates CD8+ T killer cells which help to develop cell mediated immunity that is useful against viral infections, fungal infections, other intracellular infections and malignancy. Hence, destruction of CD4+ T cells leads to lack of both hormonal & cell mediated immunity, leading to severe immunodeficiency.

Stages of HIV Infection:

HIV infection has a spectrum of manifestations including the window period, asymptotic phase and early and late symptomatic phase. The term AIDS is used to denote the late symptomatic phase, which is only the tip of the iceberg. For every AIDS patient there are at least five to ten early symptomatic cases and hundred to two hundred asymptomatic cases.

Window period: This is a period from the time of entry of HIV to seroconversion that is ELISA positivity. It usually lasts for 6 to 12 weeks. During this phase a person can be labeled false negative by blood bank. However doing p24 antigen testing or PCR can shorten this period..

Asymptomatic phase: This is a period from seroconversion till patient develops significant symptoms related to HIV. During this period the viral load is low & fluctuant and antibody titers are high. In adults it lasts for 5 - 15 years. In children infected vertically it lasts for few months to few years & in children infected through blood products it lasts little loner.

Symptomatic phase: This is the period from the time patient starts showing symptoms or signs related to HIV till he develops full - blown immunodeficiency & dies due to it. In the early phase patient may have clinical manifestations, which are nonspecific & non - AIDS defining. This is the early symptomatic phase, which can go on for months to few years. Later on, the patient develops severe immunodeficiency & all the complications related to it. This is the phase of AIDS or late symptomatic phase. Usually the patient has poor prognosis after this & dies in few months to few years time.

In children infected vertically, 40% develop AIDS by 1 year, 60% by 2 years and 80% by 5 years - only 10 to 15% survive up to 10 years. In children infected by blood products the median period to AIDS is 3.5 years and that in adults 5 to 10 years.

Modes of transmission:

There are three modes of transmission: sexual, vertical and parenteral.

Sexual Route: Cervical secretions and semen are rich sources of HIV. The chances of transmission are 0.01 to 0.1 from infected woman to man and 0.001 to 0.01 from infected man to woman per intercourse. These chances are increased if the woman has open discharging wounds due to other STIs. It is also increased with anal intercourse as in homosexuals or by having multiple partners. It is a common route in adults and adolescents. In a small child it can follow sexual abuse usually from a close relative or a familiar person. The main causes of high - risk sexual behavior are ignorance, over confidence, ill effects of media, broken families & prolonged separation from wife when men come to cities to work

Parenteral route:Parenteral transmission can occur by infected blood or blood products or by other ways.

Blood & Blood products:Blood & blood components can lead to HIV infection & accounts for 15 - 20 % of pediatric HIV cases. It occurs when either the blood is not tested properly or when collected during the window period. If P24 antigen testing is done along with ELISA, the window period can be shortened to less than 2 weeks & can decrease the changes of blood related HIV infection. Other blood products like plasma, FFP, cryoprecipitate, platelets, factor concentrate can all transmit HIV infection.

Other Parenteral Route:HIV can be transmitted by using unsterile infected needles, needle stick injuries to medical personnel, especially hypodermic needles, mouth to mouth resuscitation, exposure to infected material, sharing infected needles by intravenous drug abusers, tattooing or ear piercing by infected needles or sharing infected razors etc. Autoclaving, proper boiling for at least ten minutes, chemical sterilization and hand washing with soap and water etc can prevent such transmission. The incidence of HIV transmission following needle stick injury is 0.3%.

Vertical Route: It is the major route of transmission in children and accounts for 85% of all cases. The efficacy of vertical transmission is roughly 30 - 40%. It is more common with vaginal traumatic delivery, preterm birth, chorioamnionitis and in the first of the twin than the second. It is more common when the mother breast - feeds the child, especially the colostrum and beyond 4months of age, or when she has sore nipples. Lastly it can be blocked by various interventions including anti retroviral drugs given to mother before birth and to the baby after the birth.

Efficacy of transmission by various modes:

Vertical	20 - 50% without intervention, 8 - 110% with intervention using AZT/Nevirapine
Male to female	0.001 - 0.01%
Female to male	0.01 - 0.1%
Anal intercourse	2 - 3%
Needle stick injury	0.3% without interventions.
Blood & blood products	100%

Last created on 23-02-2001
Last updated on 28-05-2007