Perinatal Antiretroviral Intensification to Prevent Intrapartum HIV Transmission When Antenatal Antiretroviral Therapy Is Initiated Less Than 8 Weeks Before Delivery

Advancing Research and Development of Anti-infectives for Children: A Clinical Development Perspective

The HIV treatment landscape for adults has progressed dramatically in recent decades; however, paediatric populations continue to experience delayed and limited access to effective and safe antiretroviral therapy options. Despite current incentive programs, formulation research and development and approved drug dosing for children have been limited, particularly for neonates (aged <4 weeks). Regulatory approval of drug formulations and dosing in children may lag behind adult approvals by years. Formulation and trial design adjustments complicate paediatric drug development, all of which are vital to accommodate for physiological differences, organ maturation, and rapid weight gain, which are most significant in the youngest children. To facilitate more rapid anti-infective drug development for paediatric populations, regulatory agencies provide guidelines that include extrapolating efficacy and safety data from relevant populations; using pharmacokinetic (PK) bridging and modelling to reduce sample sizes and limit the number of PK studies needed before efficacy analyses; and enrolling age- or weight-based cohorts in parallel rather than sequentially for clinical trials. Ensuring access to approved drugs poses an additional challenge, as uncertainty in demand leads to manufacturing and supply complexity with potentially higher costs that can be a barrier to uptake. Here we summarize challenges in drug development for children living with HIV, which are not unique to antiretrovirals. We aim to propose strategies for how model-based approaches and global partnerships can overcome some of these barriers to accelerate paediatric drug development, with particular reference to HIV, and how lessons learnt from HIV could be extended to other anti-infectives.

Novel Approaches to Postnatal Prophylaxis to Eliminate Vertical Transmission of HIV

Despite progress in providing antiretroviral therapy to pregnant women living with HIV, a substantial number of vertical transmissions continue to occur. Novel approaches leveraging modern potent, safe, and well-tolerated antiretroviral drugs are urgently needed.

Optimizing the World Health Organization algorithm for HIV vertical transmission risk assessment by adding maternal self-reported antiretroviral therapy adherence

BACKGROUND

The World Health Organization (WHO) risk assessment algorithm for vertical transmission of HIV (VT) assumes the availability of maternal viral load (VL) result at delivery and early viral control 4 weeks after initiating antiretroviral treatment (ART). However, in many low-and-middle-income countries, VL is often unavailable and mothers' ART adherence may be suboptimal. We evaluate the inclusion of the mothers' self-reported adherence into the established WHO-algorithm to identify infants eligible for enhanced post-natal prophylaxis when mothers' VL result is not available at delivery.

METHODS

We used data from infants with perinatal HIV infection and their mothers enrolled from May-2018 to May-2020 in Mozambique, South Africa, and Mali. We retrospectively compared the performance of the WHO-algorithm with a modified algorithm which included mothers' adherence as an additional factor. Infants were considered at high risk if born from mothers without a VL result in the 4 weeks before delivery and with adherence <90%.

RESULTS

At delivery, 143/184(78%) women with HIV knew their status and were on ART. Only 17(12%) obtained a VL result within 4 weeks before delivery, and 13/17(76%) of them had VL ≥1000 copies/ml. From 126 women on ART without a recent VL result, 99(79%) had been on ART for over 4 weeks. 45/99(45%) women reported suboptimal (< 90%) adherence. A total of 81/184(44%) infants were classified as high risk of VT as per the WHO-algorithm. The modified algorithm including self-adherence disclosure identified 126/184(68%) high risk infants.

CONCLUSIONS

In the absence of a VL result, mothers' self-reported adherence at delivery increases the number of identified infants eligible to receive enhanced post-natal prophylaxis.

Zika Virus Immunoglobulin G Seroprevalence among Young Adults Living with HIV or without HIV in Thailand from 1997 to 2017

Zika virus (ZIKV) epidemiological data in Thailand are limited. We assessed ZIKV IgG seroprevalence among young adults during 1997–2017 and determined factors associated with ZIKV IgG seropositivity. This retrospective laboratory study included randomly selected subjects aged 18–25 years participating in large clinical studies conducted in Thailand during 1997–2017. Stored plasma samples were analyzed for ZIKV IgG using an ELISA test (Anti-Zika Virus IgG, EUROIMMUN, Lübeck, Germany). Sociodemographic, clinical and laboratory data were used in univariable and multivariable analyses to identify factors associated with ZIKV IgG positivity. Of the 1648 subjects included, 1259 were pregnant women, 844 were living with HIV and 111 were living with HBV. ZIKV IgG seroprevalence was similar among the HIV-infected and -uninfected pregnant women (22.8% vs. 25.8%, p-value = 0.335) and was overall stable among the pregnant women, with a 25.2% prevalence. Factors independently associated with ZIKV IgG positivity included an age of 23–25 years as compared to 18–20 years, an HIV RNA load below 3.88 log₁₀ copies/mL and birth in regions outside northern Thailand. Our study shows that a large proportion of the population in Thailand probably remains susceptible to ZIKV infection, which could be the ground for future outbreaks. Continued surveillance of ZIKV spread in Thailand is needed to inform public health policies.