HomeMy WebLinkAbouttuberculosis-in-alameda-county-2019-archivePATIENT DEMOGRAPHICS
Similar to previous years, a majority of TB cases were
male (60.5%). During 2019, the largest proportion of
TB cases occurred among adults 65 years old and older
(37.7%), and the lowest proportions occurred among
children 0 to 4 years old (0.0%) (Table 1).
OVERVIEW
During 2019, 114 tuberculosis (TB) cases were reported
to Alameda County (excluding the City of Berkeley).
The 2019 TB case rate in Alameda County was 7.4 cases
per 100,000 residents, a 26% decrease from the 2018
rate. The 2019 rate ranks seventh among all jurisdictions
in California and is 0.5-fold higher than the California
state rate of 5.3 cases per 100,000 residents. Compared
to other Bay Area jurisdictions, the Alameda County
rate ranks lower than San Francisco (13.4 per 100,000),
Santa Mateo (8.5 per 100,000), and San Clara (8.4 per
100,000), but higher than Solano (7.0 per 100,000), and
Contra Costa (5.0 per 100,000) counties.
Figure 2: Incident TB Cases (2019)
by Place of Birth, Alameda County
Figure 1. Number of Tuberculosis Cases and Rate per 100,000,
Alameda County, 2010-2019
The majority of 2019 TB cases (98.2%) occurred among non-White residents (Table 1). From 2017 to 2019, Asian/
Pacific Islander (API) residents in Alameda County had an average annual case rate of 20.7 cases per 100,000 residents,
followed by Hispanic residents at 4.4 cases per 100,000 residents.
During 2019, 91.2% of TB cases were born outside of the U.S. (Table 1). The most frequent birthplaces outside of the
U.S. remain the Philippines, India, China, Mexico, and Vietnam (Figure 2). The 2017-2019 average annual case rate for
cases born outside of the U.S. was 23.3 per 100,000, almost 18 times the rate for cases born in the U.S. (1.3 per
100,000). For 2019 cases born outside of the U.S., 64.4% had resided in the U.S for 10 years or more before being diag-
nosed with TB.
The largest proportion of 2019 TB cases occurred among residents of Oakland (28.9%), Fremont (22.8%) and Hayward
(14.0%). Five-year average rates were highest in Downtown and East Oakland, and South Fremont (over twice the five-
year county average of 8.6 per 100,000) (Figure 3).
Table 1. Number of TB Cases and Rates per 100,000 during
2017-2019, Alameda County
Tuberculosis Fact Sheet
Alameda County 2019
CLINICAL CHARACTERISTICS
Of all 2019 TB cases, 75.4% had any pulmonary in-
volvement and 24.6% were extrapulmonary only (Table 2).
Of all pulmonary cases, a majority (50.0%) were acid-fast
bacilli (AFB) smear-negative and 65.1% did not have evi-
dence of cavitary disease on chest radiography. Only 3.5%
of 2019 TB cases were co-infected with HIV. The most
common comorbidity was diabetes (23.7%).
DRUG RESISTANCE
Fewer drug-resistant isolates were identified among culture-
positive cases during 2019 when compared to 2018 (12.8%
vs 20.0%), but a similar to proportions detected during
2015-2017 (12.8% vs. 4.8%-11.5%). During 2019, 12 TB
cases were resistant any TB treatment drug, and 9 to at least
one first-line treatment drug (isoniazid, rifampin, ethambu-
tol or pyrazinamide). Of all TB cases with drug susceptibil-
ity tests reported, 6 cases (6.4%) were resistant to isoniazid
only, 3 (3.2%) were resistant to pyrazinamide only, and 1
(1.1%) case was resistant to isoniazid and streptomycin.
Alameda County had two multidrug resistant TB cases (one
resistant to isoniazid, rifampin, pyrazinamide, and etham-
butol; and one resistant to isoniazid with susceptibility to
rifampin, but had molecular mutations detected that have
been associated with multidrug-resistant TB cases).
DIAGNOSTIC TESTING
Among 2019 TB cases with any pulmonary disease, 67.4%
received a nucleic acid amplification (NAA) test at diagno-
sis, a lower proportion than among 2018 cases (73.9%).
Similar to 2018, more 2019 cases with positive sputum
AFB smears received NAA tests compared to patients with
negative sputum AFB smears (80.4% and 89.4%, respec-
tively); a smaller proportion of 2019 cases with negative
sputum AFB smears received a NAAT test compared to
2018 (50.0% and 62.3%, respectively).
SUMMARY
P a ge 2 T u b e r c u l o s i s F a c t S h e e t
1000 San Leandro Blvd, First Floor, San Leandro, CA 94577
Phone: (510) 667-3096 | Fax: (510) 273-3916
http://www.acphd.org/tb.aspx
Last updated March 11, 2020
For questions or additional information, contact:
Alameda County Public Health Department
Tuberculosis Control Section
TB remains an important public health problem in Alameda County. Preliminary analyses have not identified a specific
cause for the reduction in TB cases and rates in Alameda County; however, one possible explanation is that the declines
in cases and rates may be due to natural variation that has been observed in previous years. A large proportion of Ala-
meda County TB cases continue to occur among older adults, those born outside of the U.S., and non-U.S.-born cases
who have been in the U.S. for 10 years or more before TB diagnosis; all are known risk factors for latent TB infection
(LTBI). Reports have also indicated that 80%-85% of all TB cases are due to LTBI reactivation. Therefore, identifying
and treating LTBI is a key TB control strategy. TB Control also continues to encourage early diagnosis through the use
of NAA tests, as this practice may facilitate earlier TB treatment initiation and reduce disease transmission.
Figure 3: Average Annual TB Rates per 100,000 by Zip Code
(2015-2019), Alameda County