02140nas a2200205 4500000000100000008004100001260003400042653002600076100002400102700001200126700001100138700001200149700001500161700001400176700001500190700001100205245016200216856009000378520146600468 2021 d bCold Spring Harbor Laboratory10aPost-MDA surveillance1 aCadavid Restrepo AM1 aGass KM1 aWon KY1 aSheel M1 aRobinson K1 aGraves PM1 aFuimaono S1 aLau CL00aPotential use of antibodies to provide an earlier indication of lymphatic filariasis resurgence in post-mass drug administration surveillance, American Samoa uhttps://www.medrxiv.org/content/medrxiv/early/2021/12/02/2021.11.29.21267031.full.pdf3 a

Objectives

Under the Global Programme to Eliminate Lymphatic Filariasis (LF), American Samoa conducted seven rounds of mass drug administration between 2000 and 2006. The territory passed transmission assessment surveys (TAS) in 2011 (TAS-1) and 2015 (TAS-2) based on World Health Organization guidelines. In 2016, the territory failed TAS-3, indicating resurgence. This study aims to determine if antibodies (Ab) may have provided a timelier indication of LF resurgence in American Samoa.

Methods

We examined school-level Ag and Ab status (presence/absence of Ag- and Ab- positive children) and prevalence of single and combined Ab responses to Wb123, Bm14, Bm33 Ags at each TAS. Pearson’s chi-squared tests and logistic regression were used to examine associations between school-level Ab prevalence in TAS-1 and TAS-2 and school-level Ag status in TAS-3.

Results

Schools with higher prevalence of Wb123 Ab in TAS-2 had higher odds of being Ag-positive in TAS-3 (odds ratio [OR] 24.5, 95% CI:1.2-512.7). Schools that were Ab-positive for WB123 plus Bm14, Bm33 or both Bm14 and Bm33 in TAS-2 had higher odds of being Ag-positive in TAS-3 (OR 16.0-24.5).

Conclusion

Anti-filarial Abs could provide earlier signals of resurgence and enable a timelier response. The promising role of Abs in post-MDA surveillance and decision making should be further investigated in other settings.