Nosocomial child-to-child transmission of HIV

Horizontal HIV transmission to children of HIV-uninfected mothers: A case series and review of the global literature

BACKGROUND

Vertical transmission is the predominant route for acquisition of HIV infection in children, either in utero, intrapartum or postnatally through breast feeding. Less frequently, children may acquire HIV by horizontal transmission. Horizontal transmission may be healthcare-associated (infusion of HIV-contaminated blood products, use of contaminated needles, syringes and medical equipment, or through ingestion of HIV in expressed breastmilk). Community-acquired HIV transmission to children may occur following surrogate breastfeeding, pre-mastication of food, and sexual abuse.

METHODS

Children with suspected horizontally acquired HIV infection were identified by retrospective folder review of existing patients (2004-2014) and by prospective interview and examination of new patients (from 2009 onwards), at a hospital-based paediatric antiretroviral clinic in Cape Town, South Africa. The global literature on horizontal HIV transmission to children (1 January 1986-1 November 2019) was reviewed, to contextualize the local findings.

RESULTS

Among the 32 children with horizontal HIV transmission (15 identified retrospectively and 17 prospectively), the median age at first diagnosis was 79 months (interquartile range 28.5-91.5); most children (90.6%) had advanced HIV disease at presentation. HIV transmission was considered healthcare-associated in 15 (46.9%), community-associated in ten (31.3%), possibly healthcare or community-associated in five (15.6 %); and unknown in two children (6.3%).

CONCLUSION

Horizontal HIV transmission to children is an important public health issue, with prevention efforts requiring intervention at healthcare facility- and community-level. Greater effort should be made to promptly identify and comprehensively investigate each horizontally HIV-infected child to establish possible routes of transmission and inform future prevention strategies.

Horizontal transmission of HIV-1 infection in a child: With phylodynamic evidence-case study

Mother-to-child transmission is the predominant mode of transmission of HIV infection in children. Occasionally, horizontal transmission has also been reported. We report a child who was diagnosed HIV positive at the age of 3.5 years born to HIV-negative mother. Based on the available histories, no alternative modes of HIV transmission could be implicated. However, the paternal grandmother of the child was found to be HIV infected. To explore the likelihood that this HIV-infected relative was the most likely source from which this child acquired HIV infection postnatally, Bayesian phylodynamic analysis of the HIV of the child and parental grandmother was performed, which showed evidence of linkage of HIV transmission from an HIV-infected paternal grandmother to a child living with her through unknown route. Studies to identify modes of nonvertical HIV transmission may be useful in devising strategies to avert such nonvertical infections.

Transmission of Drug-Resistant HIV-1 from an Infected Individual to a Caregiver

Objective

To describe a suspected case of intrafamilial transmission of drug-resistant HIV-1 from an infected individual to his caregiver.

Methods

HIV-1 protease, reverse transcriptase, nef and gp41 DNA sequences were determined from plasma samples after RNA extraction and nested RT-PCR. Phylogenetic trees were generated using neighbour-joining methods.

Results

HIV-1 infection was diagnosed in an individual (index) following the death of her HIV-infected adopted son (source). The index case cared for her son in the 9 months prior to his death. No obvious instances of contact with bodily secretions or other traditional risk factors for HIV transmission were identified, although the index case had mild eczema. At time of death, the source case's HIV plasma viral load was >1,000,000 HIV copies/ml. Genotyping of the protease and reverse transcriptase of both the source and index samples revealed similar drug-resistance mutations despite the index case being antiretroviral-naive. Both source and index V3 genotypes were consistent with syncytium-inducing virus. The mean pairwise amino acid identity between the source and index samples was 97.0%, 99.2%, 92.6% and 94.6% in protease, reverse transcriptase, nef and gp41, respectively. The source and index sequences clustered together on phylogenetic trees when compared with 50 randomly selected sequences from British Columbia.

Conclusion

Although exceptionally rare, our case demonstrates transmission of drug-resistant HIV-1 from an infected individual to his caregiver in the absence of traditional risk factors. It should be noted that the source had a very high viral load during the terminal phase of his illness.

Molecular investigation of transmission of human immunodeficiency virus type 1 in a criminal case

Very few criminal cases involving human immunodeficiency virus type 1 (HIV-1) transmission have been described. We report on an HIV-1 transmission case with a child being infected by an HIV-1-positive man. The objective was to determine through molecular epidemiology and phylogenetic analyses whether HIV-1 from the HIV-1-positive man could be the source of infection in the HIV-1-positive child, as claimed by the authorities. We conducted genetic analysis of three different parts of the HIV-1 genome (gag, pol, and env) by PCR, direct-sequencing, and phylogenetic analyses. We used maximum likelihood, maximum parsimony, and neighbor-joining methods for the phylogenetic analyses to investigate whether the sequences from the man and the child were related. We found that the viral sequences from the man and the child formed separate clusters in all of the phylogenetic analyses compared to the local controls. A unique amino acid deletion was identified in the C2-V3-C3 region of the env gene in the virus from the man and the child. These results were used in the criminal court to elucidate whether the virus from the man was related to the virus from the child. In summary, the results from the phylogenetic analyses, the sequence distances between the virus from the man and the virus from the child, and the identification of the unique molecular fingerprint in the env gene together indicated that the virus from the man and the virus from the child were epidemiologically linked.

Management of HIV-infected children in the home and institutional settings. Care of children and infections control in schools, day care, hospital settings, home, foster care, and adoption

The likelihood of high-risk pediatric exposure to HIV infection, other than perinatal exposure, has been shown to be low in most cases, and HIV PEP should be considered on a case-by-case basis. Generic considerations in the management of children who have become HIV infected emphasizes the principles of inclusion, maintaining confidentiality of a child's HIV status, and notifying those who need to know about the HIV status to care properly for the child or adolescent. Although appropriate infection-control precautions are applicable for all children and for many pathogens, children especially HIV-infected children, exposed to such pathogens, must be managed in a timely fashion. In many cases, recommendations that are applicable in one setting are applicable in others. Some exceptions apply, including infection-control precautions in hospitals versus other settings. A few additional considerations have been made for special settings and activities, including adoption, foster care, athletics, summer camp, and other recreational activities.

Prevention of HIV infection in children

The threshold of a new century is an opportune time to review advances in the prevention of HIV infection in children. In the United States, progress in the ability to virtually eliminate perinatal HIV transmission that was unthinkable just a few years ago has been achieved. Clinicians providing care to pregnant women should educate and counsel women about HIV and strongly recommend that they be tested. They should also counsel HIV-infected women about the means available to substantially decrease the risk for HIV transmission to their infants (e.g., antiretroviral drug use, avoidance of breast-feeding, elective C-section, encouraging pregnant women to use barrier methods during sexual intercourse, and to discontinue injection drug use). This article has highlighted some of the remaining challenges that constitute barriers to achieving maximal decrease of HIV infection in children. Studies conducted in resource-poor countries have added greatly to the understanding of vertical transmission of HIV, and they are now leading to practical and affordable approaches to reduce vertical HIV transmission world-wide. The results of this research must lead to coordinated public health action and a global political commitment to extend the benefits of antiretroviral drug prophylaxis that now exist widely in the United States to more resource-poor countries.

Unusual transmissions of blood-borne viruses, with special reference to HIV

Containing virus infections in hospital and other clinical contexts depends upon a clear understanding of how they may be transmitted. The routes of transmission, infectious doses, portals of virus entry and exit, intensity of virus excretion and stability of the virus in the environment are all important considerations. Although present infection control policies may be based on the best available evidence, the risks are in some instances still not well enough defined to be sure that all reasonable precautions are in place. One way of improving infection control policies is to study unexpected and unusual viral transmissions to see whether new or previously unrecognized hazards have arisen. Examples are given where transmission of HIV and other blood borne viruses has seemed to occur outside recognized risk situations. On closer examination most of these represent known transmission modes but, where they do not, current control of infection policies may need to be reviewed.

Nosocomial HIV-transmission in an outpatient clinic detected by epidemiological and phylogenetic analyses

OBJECTIVE

To determine if a case of HIV-infection in a patient (GP) with common variable immunodeficiency, and with no known risk factors for HIV-infection, could be due to horizontal nosocomial transmission.

METHODS

For determination of time of transmission stored serum-samples from GP were analysed for HIV RNA content. Patient records were used to identify patients, who had received intravenous therapy on the same day as GP. Samples from GP and these possible source patients were identified and phylogenetic analyses of the env, gag and RT-encoding region of pol were performed. Furthermore, routines in conjunction with intravenous therapy were examined.

RESULTS

We identified a patient (FDL) harbouring virus almost indistinguishable from the virus isolated from GP. The pairwise nucleotide distance between the C2-V3-C3 region of the env and gag sequences from the two patients were 1.9 and 0.9% respectively. In addition, GP harboured HIV RNA with a foscarnet resistance mutation further lending support to virus from the foscarnet-treated FDL being the source of the infection. Interestingly, GP experienced increases in immunoglobulin production after contracting the HIV-infection, and decreases after antiretroviral-induced viral suppression. A clinical procedure which, under stressful conditions, could lead to breaches in infection control measures was identified. The source of the infection was most likely a contaminated multidose vial.

CONCLUSION

Through epidemiological and phylogenetic analyses a case of horizontal nosocomial HIV-transmission was disclosed. Identification of multidose vials as possible vehicles for horizontal nosocomial transmission recently led to the recommendation of restriction of the use of multidose vials, a recommendation supported by the present study. The study underlies the importance of a constant survey of infection control precautions.