Table 1 Summary of trachomatous inflammation—follicular (TF), Chlamydia trachomatis infection prevalence, median Pgp3 IgG seroprevalence and mean seroconversion rate (SCR) by study evaluation unit (EU)

From: Characterizing trachoma elimination using serology

Trachoma Category / Survey (Country-EU-Year)

N children (1–5 years)

N clusters

TF prevalence (%)

Infection prevalence (%)

Seroprevalence (%) (95% CrI)

SCR per 100 person-years (95% CrI)

Action needed

Kiribati-Kiritimati-2016

219

c

30

26.8

39.3 (32.7–45.5)

17.7 (13.6–22.4)

Kiribati-Tarawa-2016

615

22

41.5

29.1

50.8 (44.5–56.2)

14.4 (10.6–19.2)

Ethiopia-WUHA/Wag Hemra-2016

4384

40

51

21.6

38.2 (32.5–44)

13.4 (10.4–17.1)

Ethiopia-TAITU/Wag Hemra-2018

1487

48

54.3

16.7

33.3 (26.9–39.9)

12.3 (9.4–15.8)

Ethiopia-Ebinat-2019

510

30

42.5

7.1

28.3 (21.2–35.7)

9.4 (6.8–12.7)

Niger-PRET/Matameye-2013

1010

24

7.8

5.2

26.3 (18–34.2)

9 (6.4–12.3)

Ethiopia-Andabet-2017

307

22

48

6.6

24.1 (15.2–33.3)

7.7 (5.3–11)

United Republic of Tanzania-Kongwa-2013

2256

8

8.8

2.5

21.1 (11.1–31.2)

5.4 (3.3–8.4)

Solomon Islands-Temotu/Rennel/Bellona-2015

259

13

14.3

1.8

16.4 (8.8–23.8)

4.8 (2.9–7.6)

United Republic of Tanzania-Kongwa-2018

1307

50

7.1

3.5

12 (8.7–15.6)

4.2 (3.1–5.6)

Ethiopia-Goncha-2019

344

30

16.7

1

7.3 (2–12.8)

2.7 (1.6–4.3)

Action not needed

Malawi-Chapananga-2014

566

24

4.9

0.2

8.5 (5.3–11.8)

2.9 (1.8–4.4)

Morocco-Agdaz-2019

578

30

0.2

-

7.6 (2.6–12.5)

2.5 (1.6–3.8)

Malawi-Luzi Kochilira-2014

701

24

6.5

0.3

5.2 (3–7.6)

1.8 (1.1–2.9)

Malawi-Kasisi/DHO-2014

599

24

4.7

0.2

4.5 (0.8–8.2)

1.7 (1–2.7)

Malawi-DHO Nkwazi-2014

683

24

5.4

0.3

4.7 (2.9–6.6)

1.6 (0.9–2.7)

Gambia-River Regions-2014

446

36

3.4

-

3.1 (1.2–5.1)

1.1 (0.5–1.8)

Ghana-Wa-2016

835

24

1

0

2.8 (1.3–4.3)

1 (0.5–1.7)

Ethiopia-Woreta Town-2021

427

30

2.9

0.8

2.5 (0.7–4.4)

1 (0.5–1.7)

Ethiopia-Woreta Town-2017

166

12

2.7

0

2.4 (0–5.1)

1 (0.3–2.4)

Ghana-Bole/Sawla-Tuna-Kalpa-2016

817

24

0.7

0.1

2.6 (1.2–4.1)

0.9 (0.5–1.5)

Togo-Anie-2017

779

25

0.3

-

1.9 (0.8–3.1)

0.7 (0.3–1.2)

Morocco-Boumalne Dades-2019

632

29

0

-

1.8 (0.6–3.1)

0.6 (0.3–1.1)

Togo-Keran-2017

802

25

0.4

-

1.6 (0.1–3.2)

0.6 (0.3–1)

Ethiopia-Metema-2021

497

30

3.2

0

1.6 (0.4–2.7)

0.6 (0.3–1.1)

Ghana-Zabzugu Tatali-2016

845

23

1.3

0.2

1.8 (0.2–3.4)

0.6 (0.3–1.1)

Ghana-Jirapa-2016

703

23

0.8

b

1.2 (0.2–2.3)

0.4 (0.2–0.9)

Ghana-Nadowli-2016

787

24

0.9

0

1 (0.2–1.8)

0.4 (0.1–0.8)

Ghana-West Gonja-2016

710

24

1.4

0

1.1 (0.1–2.1)

0.4 (0.1–0.7)

Ghana-Gushegu Karagu-2016

845

24

0.9

0

1 (0.3–1.8)

0.3 (0.1–0.7)

Ghana-Tolon Kumbugu-2016

916

24

1.1

b

0.9 (0.2–1.6)

0.3 (0.1–0.7)

Ethiopia-Alefa-2017

316

22

3.2

0

0.6 (0–1.6)

0.3 (0.1–0.7)

Ghana-Saboba Cherepen-2016

718

22

0.7

b

0.6 (0–1.1)

0.2 (0.1–0.5)

Niger-MORDOR/Dosso-2015

5860

30

0.7

0

0.4 (0.1–0.6)

0.1 (0–0.2)

Unclassified

Sudan-El Seraif-2019

749

30

13.7

-

25.4 (18.1–32.7)

8.3 (6–11.3)

Sudan-Saraf Omrah-2019

697

35

10.9

-

23.5 (15.5–32.3)

7.7 (5.5–10.5)

Ethiopia-Dera-2017

335

22

14.7

0

8.6 (1.4–14.6)

3.1 (1.8–4.9)

Sudan-Kotom-2019

710

30

1.5

-

7.9 (4.1–11.9)

2.6 (1.7–3.8)

Vanuatu-Torba/Malampa/Penama/Shefa/Tafea/Sanma-2016

634

33

16.5

1.8

7.7 (5.5–10)

2.6 (1.6–3.8)

Malawi-Ngabu Ngokwe-2014

579

24

5.7

0.1

7.3 (3.3–11.4)

2.5 (1.5–3.8)

Malawi-Mkanda Gumba-2014

694

24

7.2

0.6

6.9 (4.1–9.9)

2.4 (1.5–3.7)

Papua New Guinea-Mendi-2015 a

576

c

15.5

3.9

5.5 (3.6–7.4)

2 (1.3–2.7)

Papua New Guinea-Daru-2015 a

469

24

13.6

0

5.2 (2.9–7.7)

1.8 (1–2.9)

Ethiopia-Debay Tilatgin-2019

292

30

15.8

1.2

4.3 (1.2–7.2)

1.6 (0.8–2.7)

Malaysia-Sabah-2015

1033

151

-

-

4.7 (3.3–6.1)

1.5 (1–2)

Peru-Amazonia-2020

423

21

-

-

3.8 (1.7–5.8)

1.3 (0.7–2.3)

Ethiopia-Machakel-2019

449

30

12.8

0.1

2.3 (0–4.5)

0.9 (0.4–1.7)

Papua New Guinea-West New Britain-2015

602

27

12.8

2.4

1.5 (0.2–3)

0.5 (0.2–1)

  1. CrI Bayesian credible interval, PCR polymerase chain reaction.
  2. a In the Papua New Guinea surveys, C. trachomatis infection prevalence was measured by PCR only among children who had TF, not in all children as in the other included surveys.
  3. b Three surveys from Ghana did not measure C. trachomatis infection prevalence by PCR but were classified alongside the other Ghana EUs as they were part of the same survey series that included 9 total EUs, 6 of which measured infection by PCR and were definitively considered as not requiring programmatic actions.
  4. c In these surveys, each individual participant was treated as an independent observation (no cluster sample).
  5. Surveys are grouped by trachoma category or programmatic decision (Methods) and ordered by SCR estimates as in Fig. 2 and Fig. 5. Here, seroprevalence and SCR were estimated for children aged 1–5 years, while TF and PCR-detected infection prevalence were estimated among children aged 1–9 years.
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