1 Avenir Health, Glastonbury, CT, USA. Electronic address: sforsythe@avenirhealth.org.
2 Joshua P. Cohen Healthcare Analytics, Boston, MA, USA.
3 Tufts Medical Center, Boston, MA, USA.
4 University of California Berkeley School of Public Health, Berkeley, CA, USA; Instituto Nacional de Salud Pública, Cuernavaca, México; University of Washington, Seattle, WA, USA.
5 Perinatal HIV Research Unit, University of the Witwatersrand, Soweto, South Africa.