Elimination of endemic measles transmission in Australia
Anita E Heywood, Heather F Gidding, Michaela A Riddell, Peter B McIntyre, C Raina MacIntyre & Heath A Kelly
Volume 87, Number 1, January 2009, 64-71
Table 1. Criteria used in countries that have declared measles elimination
| Country and year of declaration | Period of elimination | Population | Criteria |
|---|---|---|---|
| Australia | Since 2005 | In 2005: 21 million |
High two-dose vaccine coverage; > 95% MCV1 coverage and > 90% MCV2 coverage; geographic homogeneity |
| Low incidence of confirmed cases (0.5–7.3/million; < 1/million since 2005) | |||
| High proportion of cases imported or linked to an imported case | |||
| Containment of outbreaks (without re-establishment of a specific genotype) | |||
| Serological evidence of population immunity > 90% | |||
| Absence of endemic measles genotype | |||
| Estimations of R by several methods = 0.57–0.87 between 1999 and 2003 | |||
| Brazil 2003 |
2000–2001 | In 2000: 169.6 million |
High two-dose vaccination coverage in routine and supplementary campaigns (95% since 1997) |
| Low incidence of confirmed measles cases (36 cases in 2000, 1 case in 2001) | |||
| Case-based surveillance system with negative weekly reporting and targeted investigation within 48 hours; In 2000: 8 322 suspected measles cases discarded, 92% laboratory tested, discard rate ~4.9/100 000; In 2001: 5 598 suspected measles cases discarded, discard rate 3.3/100 000 | |||
| No endemic measles genotypes identified | |||
| Canada 2004 |
Since 1998 | In 2000: 30.7 million |
High two-dose coverage; > 95% MCV1 reported in all regions; 2nd dose implemented 1996; No data on coverage of MCV2 |
| Low numbers of reported confirmed cases (0.4–6/million from 1998 to 2001) | |||
| High proportion of reported cases imported or linked to an imported case and cluster sizes small (3/49 outbreaks/transmission foci > 15 cases) | |||
| 1998–99: laboratory testing for measles IgM performed at a rate of 17–22/100 000 population annually | |||
| Multiple genotypes detected and no endemic genotype identified since 1998 | |||
| 1998–2001: R = 0.82–0.87 | |||
| Cuba 1998 |
Since 1993 | In 1995: 10.9 million |
High vaccine coverage at age 12 months and periodic “catch-up,” “keep-up” and “follow-up” campaigns; > 98% coverage in targeted age groups |
| Low incidence of laboratory confirmed cases; In 1989–1992, < 20 laboratory-confirmed cases reported annually. Last cases reported July 1993 | |||
| Strengthened surveillance including screening of suspected cases | |||
| Absence of circulating virus | |||
| England & Wales 2003 |
1995–2001 | In 2001: 52 million |
“High routine vaccination coverage”; MCV1 coverage > 90% until 1998, recent decline to 84%; MCV2 introduced in 1996 |
| “High herd immunity” as seen by low number of reported cases (1995–2001: 0.2–8.8/million population, average 1.8/million population/year) and small number of large clusters (4 clusters with 10–24 cases and 4 clusters with 25+ cases) | |||
| “High” proportion of cases imported/import-linked (23% of sporadic cases and 43% of clusters involving 108 cases) | |||
| Enhanced surveillance including laboratory confirmation of suspected cases; 66% of suspected cases tested (IgM oral fluid sample); ~2600 non-measles suspected cases reported per year (~4.4/100 000/year) | |||
| Wide variety of genotypes detected with absence of previously common genotype; “High” proportion of sporadic cases with distinct genotypes | |||
| R = 0.51–0.7 using variety of methods | |||
| Finland 1994 |
Since 1994 | In 1995: 5.1 million |
High two-dose vaccine coverage (97% in targeted programme) |
| Low incidence of serologically confirmed cases since 1987; 13 serologically confirmed cases in 1993. Decline to “almost zero” incidence; No further information reported | |||
| Mexico 2004 |
1996–2000 | In 2000: 99.7 million |
High two-dose vaccine coverage; > 95% coverage ages 1–6 years since 1996, 97.6% coverage ages 6–10 years since 1999 |
| Low number of reported cases; Zero cases 1996–1999, 2–12 cases per year since with 30 cases in 2000; “Limited” local spread | |||
| Active case ascertainment, e.g. 3.5 million health centre/hospital charts reviewed during outbreak in 2000 | |||
| Sensitive rash illness surveillance system including negative weekly reporting; > 10 000 febrile rash illnesses investigated for measles per year since 1994 (discard rate ~10/100 000) | |||
| Since 1994, > 80% of febrile rash illnesses reported have been investigated within 48 hours of report, with a serum and urine sample collected 6–20 days after rash onset; Since 1996, laboratory specimens have been sent in a timely fashion for > 80% of suspected cases | |||
| Republic of Korea 2006 |
2001–2006 | In 2000: 46.8 million |
MCV2 coverage 95–99.9%; Uniformly high in all 16 provinces; 2004 seroprevalence study: 91.7–92.9% school children immune |
| Measles incidence of < 1 case per million since 2002 (between 0.12–0.27/million) | |||
| Incidence of suspected cases 2002–2006, 1.2–3.0 per 100 000 | |||
| Surveillance system: Adequate serological specimens collected from ~93% of reported suspected cases; Results from 100% of specimens available within 7 days of receipt to laboratory; 85% of suspected cases investigated within 48 hours | |||
| Virus isolated from all identified chains of measles transmission | |||
| R = 0.81 in 2001, 0.7–0.8 since 2002 | |||
| USA 2004 |
Since 1997 | In 2000: 284.9 million |
High population immunity; Vaccine coverage: at least one dose (MCV1+) > 90% 19–35-month-olds, 98% at school entry; Two doses required in 48/50 states; Serological surveillance: 92–93% of population immune; susceptibility 1–4 yrs 14%, 5–9 yrs 8%, 10–19 yrs 5%, > 20 yrs 7% |
| Low incidence of disease; < 1 case per milllion 1997–1999 | |||
| High proportion linked to imported case; 1997–2001, 36% imported, 25% linked to imported case; Duration of outbreaks short (median 18 days); Long periods in which source identified as an imported case (16 periods of at least 4 weeks) | |||
| Adequate measles surveillance system; Validation of separate reporting systems including capture–recapture study, consistent detection of sporadic and imported cases, > 1/100 000 suspected cases investigated per annum | |||
| No genotype has occurred in a repeating pattern that would suggest an endemic strain of measles virus; Isolates closely related to strains currently circulating on other countries | |||
| 1997–1999: R < 0.8. | |||
MCV, measles-containing vaccine; R, reproductive number.