Antibody response dynamics to the Plasmodium falciparum conserved vaccine candidate antigen, merozoite surface protein-1 C-terminal 19kD (MSP1-19kD), in Peruvians exposed to hypoendemic malaria transmission

Table 1 αMSP1-19kD by age group. In Plasmodium-negative^a individuals, αMSP1-19kD IgG responses^b differed by age group^c, but were similar within age group at the beginning versus end of the malaria season^d.

Malaria status	Age group	Anti-MSP-1 19KD IgG response stratification	Mar., 2003 (%, n)		Feb., 2004 (%, n)		Aug., 2004 (%, n)
NEG	Adults	≤ negative cut-off	16.2%	33	38.2%	68	35.4%	40
NEG	Adults	> negative cut-off, but < 3 times negative cut-off	20.6%	17	13.5%	24	21.2%	24
NEG	Adults	≥ 3 times negative cut-off	63.2%	92	48.3%	86	43.4%	49
NEG	Children	≤ negative cut-off	54.2%	107	71.1%	118	73.3%	77
NEG	Children	> negative cut-off, < 3 times negative cut-off	23.2%	17	10.8%	18	10.5%	11
NEG	Children	≥ 3 times negative cut-off	22.6%	40	18.1%	30	16.2%	17
		p (chisq): age group by IgG response	< 0.0001		< 0.0001		< 0.0001

^aMalaria negative (NEG) = no Plasmodium infection (neither P. falciparum nor P. vivax) detected by microscopy or PCR.
^bAntibody response stratification: Negative ≤ negative cut-off; High-Positive ≥ 3 times negative cut-off; Low-Positive > Negative and < High-Positive.
^cAdults = ≥ 14 years old.
^dFebruary 2004 = beginning of transmission season. August 2004 = end of transmission season.

ISSN: 1475-2875