Table 1.

Demographics of population under observation within the Kilifi Health and Demographic Surveillance System

		2002*	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015†
Population size (person-years)
2–11 months		4414	6789	6837	7103	7830	7385	7533	8047	7152	8058	7604	7401	7930	1891
12–23 months		5087	7834	8894	8657	8745	9565	9114	9649	9927	8854	9954	9269	9178	2435
24–59 months		15 686	23 805	24 731	25 485	25 738	26 137	26 568	27 042	28 200	28 463	28 263	28 684	27 835	6951
60–143 months		29 979	45 552	47 917	50 617	52 259	53 579	55 064	56 339	57 439	58 899	59 605	61 052	62 596	15 604
Vaccinated with PCV (%)‡
2–11 months (≥2 doses)		..	..	..	..	..	..	..	..	..	79·9	76·4	81·4	87·7	84·2
12–23 months (≥1 dose)		..	..	..	..	..	..	..	..	..	76·0	84·4	85·6	89·3	91·6
24–59 months (≥1 dose)		..	..	..	..	..	..	..	..	..	62·7	66·9	74·6	82·8	86·5
60–143 months (≥1 dose)		..	..	..	..	..	..	..	..	..	7·2	15·7	24·1	32·4	42·8
Admission to hospital
All causes
	2–59 months	1131	2463	2315	1870	2006	1703	1578	1724	1455	869	1040	646	1049	257
	60–143 months	208	389	359	393	404	348	342	376	418	294	307	252	448	139
Severe pneumonia
	2–59 months	167	420	521	443	535	382	321	334	330	154	213	97	145	49
	60–143 months	20	34	41	36	35	26	18	18	28	15	9	10	13	3
Very severe pneumonia
	2–59 months	263	463	445	264	277	306	273	321	281	140	209	142	230	40
	60–143 months	25	45	36	28	41	30	23	28	43	14	23	30	43	8
Diarrhoea§
	2–59 months	130	413	480	348	422	301	283	427	218	203	145	86	132	8
	60–143 months	8	17	19	19	16	16	11	33	26	7	15	5	12	2
Positive malaria slide
	2–59 months	609	1,166	765	480	391	231	184	112	193	145	134	91	221	62
	60–143 months	109	188	106	94	106	54	38	36	83	84	84	83	155	53
Severe undernutrition¶
	2–59 months	169	411	431	345	393	263	254	335	235	152	153	115	160	39
	60–143 months	34	48	61	58	59	40	39	59	56	23	57	26	50	17
Months of pneumonia observation in the study
Clinically defined		8	12	12	12	12	12	12	12	12	9	11	11	12	3
Radiologically confirmed		0	0	0	0	9	12	12	12	12	9	11	11	3	0
Number of pneumonia admissions with radiographs obtained
2–59 months		..	..	..	..	332	401	360	281	253	185	310	163	57	..
60–143 months		..	..	..	..	25	26	19	18	17	12	13	29	5	..
Number of admissions with radiologically-confirmed pneumonia
2–59 months		..	..	..	..	76	94	70	68	65	28	46	49	21	..
60–143 months		..	..	..	..	11	6	6	6	6	4	5	8	3	..

Population estimates are mid-year populations. In 2002 and 2015, these are multiplied by the proportion of the year under observation. PCV=pneumococcal conjugate vaccine.

^*2002 includes only May to December.

^†2015 includes only January to March.

^‡Vaccine coverages are estimated in the last week of each year except 2015 (last week of March 2015).

^§Of 5229 patients with diarrhoea, 1427 also had clinically-defined pneumonia were classified only as pneumonia.

^¶Severe undernutrition was defined as a weight-for-age Z score of less than −3 on admission to hospital.