While effective HIV treatment greatly reduces the risk of onward
transmission during breastfeeding, it does not appear that the risk is zero, a
leading paediatrician told the British HIV Association (BHIVA) conference in
London last week. Although formula feeding is the safest option in high-income
countries, some women will choose to breastfeed and healthcare professionals
should support them to do so as safely as possible.
Dr Hermione Lyall of St Mary's Hospital, London said that
she and colleagues often needed to advise patients who were doing well on HIV
treatment, with an undetectable viral load, who wished to breastfeed. Many are
aware of World Health Organization (WHO) guidelines which recommend
breastfeeding for women with HIV. Many women say that breastfeeding is expected
by their families and that they also believe it is the right thing to do.
However, WHO guidelines are primarily written for countries
with a high HIV prevalence where the lack of access to clean water means that
the risk of HIV transmission through breastmilk must be weighed against the
risks of infant malnutrition, infections and mortality posed by formula
feeding. In contexts where these risks are not present, such as the UK,
guidance recommends that mothers living with HIV stick to formula feeding.
But should the UK guidance change in the light of our
increasing understanding of the impact on HIV treatment and undetectable viral
load on the risk of transmission? Does the statement “undetectable = untransmittable”
(U=U) apply to breastfeeding as well as to sexual transmission?
There are very few data from the UK. Every year, around 1200
babies are born to women living with HIV. Since 2012, just 40 mothers have
reported that they have breastfed. All were undetectable and no transmissions
have occurred.
Most studies have been conducted in African countries or in
India. A
recent meta-analysis pooled data from studies on women who were
breastfeeding while taking HIV treatment. It found a postnatal transmission
rate of 1.1% after six months. Not included in
that review, data from 1220 mother-infant pairs in the PROMISE trial showed
a postnatal transmission rate of 0.3% after six months and 0.6% after 12
months. This suggests that the transmission risk increases with a longer
duration of breastfeeding, although mixed feeding after six months may also
have contributed.
Moreover, those studies did not correlate mothers’ viral
loads with transmissions – mothers whose HIV treatment was not fully effective probably
contributed to the transmissions that were seen in those studies. A Tanzanian
study reported at the recent European AIDS Conference (EACS) is therefore of
interest. Among 177 infants who were exclusively breastfed by mothers living
with HIV who began HIV treatment before delivery, there were two transmissions.
One was from a mother with a high viral load and the other from a mother who had
stopped taking HIV treatment.
In contrast, there were no transmissions from mothers with undetectable
viral loads. This suggests that there is a very low risk of breastfeeding transmission
when viral load is suppressed, but these are not enough data to say that U=U, Lyall
said.
Lyall recommended taking a harm reduction approach with
mothers who express a wish to breastfeed. People will make healthier choices if
they have access to adequate support, empowerment, and education, she said.
Women should be advised that formula feeding has a zero risk of HIV
transmission and is the safest thing to do. Breastfeeding is an option, but
women must understand that they are taking a risk, even if it is a very small
risk.
Advice should take account of the risk factors for HIV
transmission during breastfeeding. Women who wish to breastfeed should be highly adherent to HIV treatment,
have a viral load below 50 copies/ml (ideally throughout the pregnancy), should
minimise the duration of breastfeeding, should engage with their
multidisciplinary team and should be willing to be followed up monthly.
The Children’s HIV Association (CHIVA) is collaborating with
patient advocates to produce patient information which simplifies the complex
information on this topic, takes into account women’s preferences and attempts
to guide them to the safest approach. It will include three key safety points
that women should remember while they breastfeed:
- No virus: Only breastfeed if your HIV is undetectable.
- Happy tums: Only breastfeed if both you and your baby are free
from tummy problems.
- Healthy breasts for mums: Only breastfeed if your breasts
and nipples are healthy with no signs of injury or infection.