Table 3.

Difference in prepatent period in unvaccinated participants, PCR compared with thick smear*

Study	Mean prepatent period by PCR, days	Mean prepatent period by thick smear, days	Difference in prepatent period, days	95% confidence interval	Significance testing
NF54 challenge (n = 36) (aseptic mosquitoes)	7.5	10.9	3.4	2.8–3.9	P < 0.001
NF54 challenge (n = 18) (non-aseptic mosquitoes)†	8.7	11.5	2.8	1.8–3.8	P < 0.001
Parenteral challenge (n = 24) (intradermal)	10.7	13.6	2.9	2.0–3.7	P < 0.001

Polymerase chain reaction detected Plasmodium falciparum infection 3 days earlier than thick smears (two-way ANOVA with Bonferroni posttests), as has been shown in other studies.⁵¹ Our center has not performed head-to-head trials comparing prepatent period by blood smear and PCR for 7G8 trials.

* Calculated using two-way ANOVA with Bonferroni posttests.

^†This PCR was performed at the National Institutes of Health with a different methodology and different sensitivity from those used in the other two trials.