Short Communication: Heightened HIV Antibody Responses in Postpartum Women as Exemplified by Recent Infection Assays: Implications for Incidence Estimates

Abstract

Laboratory assays that identify recent HIV infections are important for assessing impacts of interventions aimed at reducing HIV incidence. Kinetics of HIV humoral responses can vary with inherent assay properties, and between HIV subtypes, populations, and physiological states. They are important in determining mean duration of recent infection (MDRI) for antibody-based assays for detecting recent HIV infections. We determined MDRIs for multi-subtype peptide representing subtypes B, E and D (BED)-capture enzyme immunoassay, limiting antigen (LAg), and Bio-Rad Avidity Incidence (BRAI) assays for 101 seroconverting postpartum women, recruited in Harare from 1997 to 2000 during the Zimbabwe Vitamin A for Mothers and Babies trial, comparing them against published MDRIs estimated from seroconverting cases in the general population. We also compared MDRIs for women who seroconverted either during the first 9 months, or at later stages, postpartum. At cutoffs (C) of 0.8 for BED, 1.5 for LAg, and 40% for BRAI, estimated MDRIs for postpartum mothers were 192, 104, and 144 days, 33%, 32%, and 52% lower than published estimates of 287, 152 and 298 days, respectively, for clade C samples from general populations. Point estimates of MDRI values were 7%–19% shorter for women who seroconverted in the first 9 months postpartum than for those seroconverting later. MDRI values for three HIV incidence biomarkers are longer in the general population than among postpartum women, particularly those who recently gave birth, consistent with heightened immunological activation soon after birth. Our results provide a caution that MDRI may vary significantly between subjects in different physiological states.

Identification and validation of a multi‐assay algorithm for cross‐sectional HIV incidence estimation in populations with subtype C infection

“…The mean window period we calculated for the current LAg algorithm in this study (142 days) was nearly identical to the 2 year MDRI for this algorithm that was calculated by the Consortium for the Evaluation of the Performance of HIV Incidence Assays (CEPHIA; 141 days, 95% CI: 123 to 160 days) ; the CEPHIA estimate was based on a sample set that was not limited to subtype C samples. A recent report cited a much lower MDRI for the LAg‐Avidity assay (101 days) .…”

Trends of HIV incidence and prevalence among men who have sex with men in Beijing, China: Nine consecutive cross-sectional surveys, 2008-2016

“…During the past decade, several laboratory incidence assays have been conducted, and the HIV-1 BED-capture-enzyme immunoassay (BED-CEIA) being the most commonly used for HIV surveillance. The method is an IgG capture enzyme immunoassay used to detect and distinguish recent from long-term HIV-1 infections, and has been used widely to estimate HIV incidence in many areas, both in China [ 10 – 14 ] and outside of China [ 15 – 19 ]. While limited investigation was found to examine the trend of HIV incidence and factors causing the trend, especially in a metropolitan of huge mobile population for a long period.…”

A systematic review of limiting antigen avidity enzyme immunoassay for detection of recent HIV-1 infection to expand supported applications

“…For example, we found two studies done using samples collected from the Zimbabwe Vitamin A for Mothers and Babies Trial, where postpartum women and their new-borns were recruited and followed, to observe effects of maternal and/or neonatal vitamin A in reducing HIV transmission, comorbidities, and child mortality. 54 , 55 Both studies found that MDRI and FRR estimates were lower compared to other studies. This further demonstrates the need to understand how HIV infection among these key populations affect the use of LAg in identifying recent infections.…”