Tuberculosis in New Zealand: Annual Report 2017

Thursday 29th July 2021


Summary

This report describes the epidemiology of tuberculosis in New Zealand for 2017 as well as trends during the past 5–10 years.

Incidence: Tuberculosis disease (TB) is a notifiable condition in New Zealand. The incidence rate for TB in 2017 was 6.4 per 100,000 population (308 cases), similar to the rates in the previous two years, and a small decline from the average of 6.7 per 100,000 for the preceding seven years. The majority of TB notifications were for new disease, with relapse/reactivation cases making up a small number of notifications.

Demography: Geographically the highest notification rates for new TB cases in 2017 were reported from Auckland, Counties Manukau and Hutt Valley DHBs, with the Auckland region accounting for just over 50% of new TB cases. Females had a slightly higher rate for new TB notifications in 2017 (6.2 per 100,000,15 cases) than males (6.1 per 100,0001 143 cases). By age group the highest notification rate for new TB cases in 2017 was in the 15–39 years age group (10.4 per 100,000, 170 cases). The highest rates were reported in the Asian ethnic group (37.2 per 100,000, 205 cases) followed by Pacific peoples (12.2 per 100,000, 36 cases), MELAA (11.2 per 100,000, 6 cases), Māori (3.4 per 100,000, 24 cases) and European/Other (0.7 per 100,000, 23 cases) ethnic groups. As in previous years, higher rates of TB occurred in socioeconomically deprived areas.

Place of birth and trends by country of birth: People born outside New Zealand accounted for 83.4 % of notifications of new TB cases in 2017. The rate of TB among this population group was 12 times higher than the rate in those born in New Zealand. Being born in India or the Philippines were the most commonly reported risk factors for new TB cases in New Zealand in 2017. Of the new TB cases in people not born in New Zealand, nearly one fifth of notifications occurred in the first year after arrival in New Zealand and just over half occurred within 5 years. Between 2008 and 2017, among people not born in New Zealand, there was an 18.8% increase in the number (+39) and a 19% increase in rate of TB. In comparison, there was a 53% decrease in the number (-26) and a 36% decrease in the rate of TB among people born in New Zealand.

Diagnosis: Over three quarters of new TB cases present symptomatically to their health practitioner. The percentage of cases identified through immigrant / refugee screening has increased over three - fold (4% to 14%), within the last 4 years, whilst the percentage of cases identified through contact follow up has fallen to 4.4% from 8% over the same period.

Transmission within New Zealand: In 2017, the 3-year moving average annual rate for new TB in New Zealand-born children aged <15 years (a proxy for recent transmission within the country), [5] was 1.2 per 100,000; a 60% reduction from the peak of 3.0 per 100,000 in 2008.

Treatment standards: In 2017, 98.3% (290/295) of new TB cases received treatment. In just under two fifths (39.0%) of cases of new pulmonary TB (PTB), a date of symptom onset was not reported. For those where this information is documented, almost a third (32%) of the cases experienced an interval of greater than 3 months before the start of treatment. In 2016 the proportion of people with new TB who received appropriate treatment was 98.9% (280/283), of whom 86.1% (241/280) completed treatment; the majority of the remaining 13.9% most commonly did not complete treatment because they died (4.3%, 12/280), transferred/moved overseas (7.1%, 20/280), had adverse effects (1.8%, 5/280), or refused to complete treatment (0.7%, 2/280).

Outbreaks and molecular clusters: There were three outbreaks of M. tuberculosis with 11 associated cases in 2017. Two new M. tuberculosis molecular clusters were identified in 2017. Over one-third of the isolates that underwent molecular typing between 2013 and 2017 were part of a cluster, of which 90.8% had fewer than five cases.

Drug susceptibilities: There were five cases with confirmed multi-drug resistant tuberculosis (MDR-TB) in 2017; all five cases were born overseas. There were four MDR-TB cases in 2016. Three were transferred to overseas medical care and one completed treatment in New Zealand. Between 2008 and 2017 there has been increasing streptomycin resistance among isolates from cases born overseas and this is significantly higher in 2017 (p 0.019).

Note: Click on the document links below to open. These documents are in PDF format. You will need to download the free Adobe Acrobat Reader to view them.

Report:

Tuberculosis in New Zealand: Annual Report 2017

 

DOWNLOADS

Tuberculosis in New Zealand: Annual Report 2017

Ph: +64 4 914 0700 Fax: +64 4 914 0770 Email: survqueries@esr.cri.nz