MHC polymorphism is explained by natural selection driven by the MHC-dependent impact of certain infections, inflammatory conditions, autoimmune diseases, and cancers. However, examples of human disease driving this process are rare. We evaluated the impact of HIV-1 in altering HLA-I frequencies in KwaZulu-Natal, South Africa, and the influence of antiretroviral therapy (ART) on this process. In a historical mother-child cohort in the pre-ART era (1998-2005), HIV-1 survival and vertical transmission were both strongly HLA-B dependent: "disease-susceptible" HLA-B alleles (HLA-B*18/B*45:01/B*58:02) increased adult AIDS progression and vertical transmission (OR 1.6, P = 0.01), whereas "protective" HLA-B alleles (HLA-B*57/B*58:01/B*81:01) slowed AIDS progression, and decreased vertical transmission (OR 0.57, P = 0.002). By contrast, in contemporary antenatal KwaZulu-Natal cohorts in the ART era (2015-2025) the impact of HLA-B on HIV-1 disease outcome and vertical transmission is dramatically reduced. Using these and reported data, we constructed a model to estimate the impact of HIV-1 on HLA-B frequencies in KwaZulu-Natal, both in the prevailing setting of ART and in a hypothetical counterfactual scenario where ART was never rolled out. Over the 45-y period 1990-2035, in the absence of ART, the proportion of the population possessing any "protective" HLA-B allele was projected to increase from 23 to 42% (allele frequencies increasing from 0.12 to 0.24), and the proportion of the population possessing any "disease-susceptible" HLA-B allele was projected to decrease from 28 to 18% (allele frequencies declining from 0.15 to 0.092). The introduction of ART radically slows HLA-B frequency change. These data therefore demonstrate the potential for natural selection from an infectious disease to alter human population genetics within decades, and for the successful roll-out of therapy to halt this process.
After sporadic reports of post-treatment control of HIV in children who initiated combination anti-retroviral therapy (cART) early, we prospectively studied 284 very-early-cART-treated children from KwaZulu-Natal, South Africa, after vertical HIV transmission to assess control of viremia. Eighty-four percent of the children achieved aviremia on cART, but aviremia persisting to 36 or more months was observed in only 32%. We observed that male infants have lower baseline plasma viral loads (P = 0.01). Unexpectedly, a subset (n = 5) of males maintained aviremia despite unscheduled complete discontinuation of cART lasting 3-10 months (n = 4) or intermittent cART adherence during 17-month loss to follow-up (n = 1). We further observed, in vertically transmitted viruses, a negative correlation between type I interferon (IFN-I) resistance and viral replication capacity (VRC) (P < 0.0001) that was markedly stronger for males than for females (r = -0.51 versus r = -0.07 for IFN-alpha). Although viruses transmitted to male fetuses were more IFN-I sensitive and of higher VRC than those transmitted to females in the full cohort (P < 0.0001 and P = 0.0003, respectively), the viruses transmitted to the five males maintaining cART-free aviremia had significantly lower replication capacity (P < 0.0001). These data suggest that viremic control can occur in some infants with in utero-acquired HIV infection after early cART initiation and may be associated with innate immune sex differences.
BACKGROUND:Abdominal wall defects (AWDs), such as gastroschisis and omphalocele, and neural tube defects (NTDs) such as open spina bifida (SB) are common congenital anomalies. These anomalies are considered a leading cause of neonatal mortality and have been advocated as bellwether conditions to measure access to surgical care.METHODS:Newborns with open SB or AWD presenting to the nursery at Queen Nandi Regional Hospital over four years (2018-2021) were retrospectively identified. Clinical and electronic database records were reviewed to determine if transfers to definitive tertiary care occurred timeously. Reasons for delays and associated morbidity and/or mortality were investigated.RESULTS:Sixty-five patients were identified and two were excluded due to unavailable or incomplete records. It took a median of 8 days (IQR 2-18 days) to reach tertiary care, with SB cases waiting significantly longer (median 16 days,IQR 8-25 days) (p = 0.000). Lack of tertiary service capacity was the main reason for delays. The COVID-19 pandemic did not affect time intervals (p = 0.676). Complications were common and overall mortality at our facility was high (n = 11/63, 17.46%).CONCLUSION:Newborns with open SB or AWDs experience marked delays in reaching definitive care. This is more pronounced for cases of SB and was not influenced by the pandemic. Lack of tertiary service capacity (including bed availability, limited staff, and theatre time) is the most important limiting factor.
Background. Poisoning has been reported as the fifth most common cause of injury-related deaths in children younger than five years worldwide. Little is known about accidental poison exposure among children at regional hospital level. Regional hospitals generally provide more specialised support to primary care facilities over a larger area. During the COVID-19 pandemic, lockdown measures may have increased home-based unintentional poisoning. Objectives. To determine the frequency, outcome and type of accidental poison exposure in children admitted to a regional hospital and compare cases before and during the COVID-19 pandemic. Methods. A review of admissions to Queen Nandi Regional Hospital in Empangeni was performed to document cases of accidental poison exposure over two years. Equal periods during 2019 and 2020 (April to December) were then compared. Children <13 years of age were included. Age, sex, date of admission, death or survival and type of poisoning were collected. Results. Cases of accidental poison exposure made up a small proportion of the total admissions over two years (n=252/5 071, 4.97%) with a low case fatality rate (0.40%). Boys made up the majority (n=132/252, 52.38%). Most were <five years old (n=220/252, 87.30%). Medicines (n=114/252, 45.24%), hydrocarbons (n=59/252, 23.41%) and pesticides (n=26/252, 10.32%) were the main types of poison. Domestic cleaner-, sanitiser- and disinfectant-related admissions were significantly increased during the pandemic (p=0.020). Conclusion. Accidental poison exposure occurs commonly in younger children. Medicines, hydrocarbons and pesticides made up the majority of cases. Domestic cleaner, hand sanitiser and disinfectant ingestion increased in the pandemic. Future research should involve primary care facilities, and risk factors as well as clinical severity should be investigated.
