HIV screening typically takes place in the first trimester, but some patients can still miss out.
Two New Zealand babies have been diagnosed with HIV passed on from their mothers for the first time in nearly 20 years.
Perinatal HIV cases were effectively eliminated in New Zealand in 2007 after routine screening was added to antenatal check-ups the previous year.
As a result, prevention methods in this country have focused primarily on groups which have higher rates of HIV, in particular men who have sex with men.
But experts say an inconsistent approach to antenatal screening around New Zealand means some pregnant patients can still miss out. The new cases were also a possible symptom of a stretched health system, they said.
The University of Otago HIV Epidemiology Group found that two children born in 2023 were diagnosed with perinatally acquired HIV last year to women who were not known to have HIV before or during their pregnancy.
Positive Women Aotearoa national co-ordinator Jane Bruning, whose organisation supports people living with HIV, said the two mothers were understood to be from overseas and came to New Zealand while they were already pregnant.
This meant they possibly missed a check-up in the first trimester of pregnancy, when screening usually takes place.
However, HIV blood tests can also be done at later stages in the pregnancy – including during delivery. If HIV is diagnosed during a birth, there is still a possibility of preventing transmission to the child.
Bruning said midwives or other healthcare workers caring for the mothers should have noted that they were from countries with high HIV rates.
“I’m sure the people who are involved in the babies’ care are feeling terrible about it, but it’s actually not okay that they weren’t tested. There were lots of red lights there for people to have done the HIV test. It’s quite negligent that this has happened.”
There is no cure for HIV, and a baby who contracts the disease will be on medication for the rest of their life. Advances in anti-retroviral treatments mean patients with HIV have a similar or better life expectancy than patients with many other chronic diseases.
While the exact circumstances of the new perinatal cases are not known, New Zealand experts highlighted overseas studies that showed that migrants sometimes do not disclose their HIV status because of fears it will affect their visa.
New Zealand does not automatically block migrants who are HIV positive. However, migrants with HIV still cite concerns about discrimination at the border, the studies said.
Dr Sue McAllister, who leads the HIV Epidemiology Group at the University of Otago, said screening changes in 2006 led to a “wonderful” period in which mother-baby HIV cases fell from a handful of cases a year to zero. However, she had been expecting cases to re-emerge.
“We were holding our breath,” McAllister said. “Hearing the difficulties about the health system and people accessing midwives and antenatal care and thinking, ‘When is this going to happen?’”
There were already clues that not all New Zealand parents were getting appropriate antenatal care and screening. Rates of perinatal syphilis – which is tested for at the same time as HIV – have been rising.
“It is a reminder that it is not the woman, it is the system,” McAllister said. “It is making sure that midwifery and antenatal care is available for everyone irrespective of where they live and who they are. And also ensuring the midwives know that HIV is still here.”
Deborah Woodley, director of Health NZ Te Whatu Ora’s Starting Well department, said the perinatal cases were “concerning” and a reminder of the importance of antenatal screening.
“While no specifics of these cases can be provided to protect privacy, HIV notifications will continue to be monitored to understand any underlying issues or areas for improvement.”
Since 2006, mothers have been screened for HIV at their first antenatal check-up, with five other diseases. In that time, 32 pregnant mothers have been diagnosed with HIV and none has transmitted the disease to her child.
There is no national guidance for the screening process, meaning some regions ask parents to opt in to screening and others ask them to opt out.
An opt-in policy has been linked to lower rates of screening.
The authors of a New Zealand Medical Journal study published last year said the opt-in approach meant doctors had to be proactive in offering a test and had to carefully balance the pros and cons – which “aggravated” potential barriers to screening.
The opt-in approach also unduly focused on HIV, even though it was one of a bundle of tests performed at a first antenatal visit. This made HIV screening seem exceptional rather than normalising it.
In 2022, Auckland and Northland switched from opt-in to opt-out as part of a trial, and the rate of patients getting tested rose from 86% to 98%.
In some regions, doctors use a blood test form which requires them to tick an extra box for HIV screening – a small but important difference which means it can be accidentally missed.
While the two perinatal cases have caused concern, the broader picture of HIV prevention in New Zealand is more positive, with overall new cases falling.
The latest HIV Epidemiology Group data showed 95 people were diagnosed with HIV last year, down from an average of around 140 a year in the pre-pandemic years. That trend was driven mostly by a fall in rates among men who have sex with men.
McAllister said falling rates were the result of having “more tools in the toolbox” for preventing HIV, including funded pre-exposure medication, rapid testing, and point-of-care testing.
She also credited a highly successful global health strategy known as U = U (Undetectable = Untransmittable), which emphasises that people with an undetectable viral load cannot transmit HIV to their sexual partner.
Isaac Davison is a senior reporter who covers Auckland issues. He joined the Herald in 2008 and has previously covered the environment, politics, social issues, and healthcare.
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