Table 1.
Prevalence of anti-chikungunya virus antibody observations for 204 Papua New Guinea military personnel participating in this study, 2019
| Military participants | Manus Island | Wewak | Total |
|---|---|---|---|
| Number of participants | 76 | 128 | 204 |
| Percentage | 36.4 | 63.6 | 100% |
| Male/female | 76/0 | 127/1 | 203/1 |
| Age range (years)a | 23–62 | 21–59 | 21–62 |
| Mean | 35.2 | 39.2 | 37.5 |
| Median | 29 | 41.5 | 34 |
| ELISA IgG+ | 39.5% (30/76) | 51.5% (66/128) | 47.1% (96/204) |
| ELISA IgG± | 13.1% (10/76) | 10.2% (13/128) | 11.2% (23/204) |
| ELISA IgG- | 47.4% (36/76) | 38.3% (49/128) | 41.6% (85/204) |
| Neutralizing assay+ | 21.1% (16/76) | 43% (55/128) | 34.8% (71/204) |
| Neutralizing assay- | 78.9% (60/76) | 57% (73/128) | 65% (133/204) |
| ELISA+, neutralizing assay+ | 18.4% (14/76) | 35.9% (46/128) | 29.4% (60/204) |
| ELISA±, neutralizing assay+ | 0% (0/76) | 4.7% (6/128) | 2.9% (6/204) |
| ELISA-, neutralizing assay+ | 2.6% (2/76) | 2.3% (3/128) | 2.5% (5/204) |
| Age, years, no. neutralizing assay positive/no. testedb | |||
| Group 1, age 20–35 years | 26% (13/50) | 22.7% (29/128) | 38.9% (42/108) |
| Group 2, age 36–50 years | 7.1% (1/14) | 14.1% (18/128) | 28.4% (19/67) |
| Group 3, age 51–62 years | 16.7% (2/12) | 6.3% (8/128) | 34.5% (10/29) |
+, positive; -, negative; ±, borderline; ELISA, enzyme-linked immunosorbent assay.
a
Age = bleeding date - date of birth.
b
No significant differences were found between the three age groups.