Mosquito bite immunization with radiation-attenuated Plasmodium falciparum sporozoites: safety, tolerability, protective efficacy and humoral immunogenicity

Table 3 Summary of immunizations in this study (1999–2002) and the previous study (1989–1999)

A	Individual study data				P value
	1999–2002^a		1989–1999
	Median	Range	Median	Range
Infected bites in the first immunization	224	138–334	148	130–210	0.0065
Total infected bites	1247	1005–1561	1092	1001–1163	0.0288
Median infected bites per immunization	214	175–260	125	109–210	0.0006
Number of immunizations	6	5–6	8.5	5–10	0.0014
Duration of immunizations (days)	206	175–239	241.5	99–547	0.0450
Median immunization interval (days)	43.5	35–48	31	23–77	0.2401
Median Interval before CHMI (days)	35	15–42	16	14–71	0.0434
Median gland grade score^a during immunization	3.5	3.2–3.9	3.2	3.0–3.7	0.0045
Median gland grade score during CHMI	2.7	2.4–3.2	3.2	2.8–3.4	0.0017

B	Combined data (1989–2002)				P value
	Protected		Non-protected
	Median	Range	Median	Range
Infected bites in the first immunization	159	130–334	148	133–250	0.4829
Total infected bites	1110	1001–1561	61170	1008–1366	0.7728
Median infected bites per immunization	138	109–260	125	112–228	0.2652
Number of immunizations	8	5–10	6	5–9	0.2293
Duration of immunizations (days)	221	99–547	196	180–455	0.3639
Median immunization interval (days)	38.5	23–77	43.5	36–57	0.3630
Median Interval before CHMI (days)	20	14–42	36	25–71	0.0088
Median gland grade score^b during immunization	3.3	3.0–3.9	3.5	3.0-3.8	0.2155
Median gland grade score during CHMI	3.1	2.4–3.4	2.7	2.4–3.2	0.0629

Part A summaries (median, range) of the immunizations in the 1999–2002 and 1989–1999 [15] studies were compared using the Mann–Whitney U test, where significance is P ≤ 0.05; these parameters were significantly different between each study except the median time between each immunization
Part B summaries of protected and non-protected subjects in each study were combined and compared using the Mann–Whitney U test, where significance is P ≤ 0.05; only the interval before CHMI (days between last immunization and CHMI) was significant
^aDerived from combining the two groups shown in Table 2
^b Gland score as defined in “Methods” section, salivary infection rates were defined as gland scores: 1–10 sporozoites = gland score 1; 11–100 sporozoites = gland score 2; 101–1000 sporozoites = gland score 3; and >1000 = gland score 4

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