MoCHiV key data (figures)

1. State of the MoCHiV cohort

The Swiss Mother and Child HIV Cohort Study (MoCHiV) was started in 2003 as a combined study of two former studies ‘Neonatal HIV Study’ and ‘HIV Pregnancy Study’. The final aim was the integration into the existing Swiss HIV Cohort Study (SHCS). Since then, as in the SHCS, a large biobank exists for all enrolled children. MoCHiV aims at preventing mother-to-child transmission and enrolls HIV-infected pregnant women and their children.

Since the beginning of the HIV epidemic in the early 1980’s until 2021, data of 2'165 children - of whom 280 were HIV positive - have been registered into MoCHiV. Of the HIV positive children, 80 were lost from follow-up or are treated by a non-cohort physician, 62 have died, and 38 are currently under follow-up in MoCHiV. 100 children reached adulthood and are now followed by the SHCS (fig. 1). Most of the HIV positive children currently under follow-up are treated with a combined antiretroviral therapy. Of the HIV negative children, 172 healthy children are currently under follow-up. They are planned to be followed for at least 2 years.


fig. 1: Overview of MoCHiV participating children

Initially, no intervention at all was available to reduce vertical transmission. Transmission rates were in the range between 20 - 25%. Later on, preventive interventions became available. First antiretroviral monotherapy with Zidovudine, then combined with elective cesarean section (ECS) were the first steps to prevent vertical transmission. Then ECS in combination with highly active antiretroviral therapy (HAART) was considered as the prevention of choice for vertical transmission of HIV. Since the HIV treatment is more successful within the last few years, the guidelines could be adjusted. According to the current guidelines, vaginal delivery is proposed if the women is under a stable therapy and no virus can be detected in her blood (fig. 2).

fig. 2: Mode of delivery in HIV positive women

The evolution of preventive interventions has been very successful. Vertical transmission rate could steadily and substantially be reduced. In the last few years no cases of transmission were registered in MoCHiV. The definitive diagnoses can be made after four to six months based on two diagnostic blood samples taken one month and four to six months after birth (fig. 3).


Figure 3: HIV Status of children born to HIV positive mothers
fig. 3: HIV Status of children born to HIV positive mothers

2. Mothers in the MoCHiV

Mothers are recruited largely from the heterosexual transmission group (79.3%). A small part of women was infected by HIV-contaminated needles during drug use (IDU). Thanks to the successful HIV-treatment some women who were perinatally infected in the 80’s and 90’s reach now the adulthood and can give birth without vertical transmission (fig. 4). Of all HIV infected women who gave birth, 54% are between 26-35 years of age at the time of delivery, 25% older than 35 years of age and a smaller part of mothers younger than 26 years of age.

Figure 4: Transmission of HIV in mothers
fig. 4: Transmission of HIV in mothers

Most of the women included in the MoCHiV until 2021 (65.8%) were already treated before pregnancy, 5.5% started antiretroviral therapy in the first trimester of pregnancy, 20.5% in the second 7.5% in the third trimester, and 0.7% were not treated. Twenty-four percent of women (N=178) received additional AZT prophylaxis during delivery (fig. 5).


Figure 5: ART Status of pregnant women
fig. 5: ART Status of pregnant women

Since the availability of HAART the treatment of HIV is successful, which is most important for the prevention of vertical transmission. For 83.4% of pregnant HIV-infected women the viral load was undetectable or <= 500 RNA-copies/ml within 2 months before delivery, 5.3% had a viral load > 500 RNA-copies/ml (fig. 6).

Figure 6: Viral load (VL) of women in the last trimester
fig. 6: Viral load (VL) of women in the last trimester

all figures