HomeMy WebLinkAbouttuberculosis-in-alameda-county-2020-archivePATIENT DEMOGRAPHICS
Similar to previous years, the majority of TB cases were
male (59%). During 2020, the largest proportion of TB
cases occurred among adults aged 65 years old and older
(41%), and the lowest proportion occurred among chil-
dren 0 to 14 years old (0%) (Table 1).
OVERVIEW
During 2020, 98 tuberculosis (TB) cases were reported
to Alameda County (excluding the City of Berkeley).
The 2020 TB case rate in Alameda County was 6.3 cases
per 100,000 residents, a 15% decrease from the 2019
rate. The 2020 rate ranks sixth among all jurisdictions in
California and is 0.5-fold higher than the California state
rate of 4.3 cases per 100,000 residents. Compared to
other Bay Area jurisdictions, the Alameda County rate
ranks lower than San Francisco (6.6 per 100,000), Santa
Mateo (6.7 per 100,000), and Santa Clara (7.7 per
100,000), similar to Solano (6.4 per 100,000), and higher
than Contra Costa (3.4 per 100,000) counties.
Figure 2: Percent of TB Cases,
by Place of Birth, Alameda County, 2020
Figure 1. Number of TB Cases and Rate per 100,000, Alameda
County, 2011-2020
The majority of 2020 TB cases (90%) occurred among non-White residents (Table 1). From 2018 to 2020, Asian/
Pacific Islander (API) residents in Alameda County had an average annual case rate of 18.6 cases per 100,000 residents,
followed by Hispanic residents at 4.0 cases per 100,000 residents.
During 2020, 92% 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, Vietnam, China, and Mexico (Figure 2). The 2018-2020 average annual case rate for
cases born outside of the U.S. was 22.3 per 100,000, 22 times the rate for cases born in the U.S. (1.0 per 100,000). For
2020 cases born outside of the U.S., 66% resided in the U.S for 10 or more years before being diagnosed with TB.
The largest proportion of 2020 TB cases occurred among residents of Oakland (30%) and Fremont (22%). Five-year
average rates were highest in Downtown Oakland and South Fremont (more than twice the five-year county average of
8.1 per 100,000) (Figure 3).
Table 1. Number of TB Cases and Rates per 100,000, Alameda
County, 2018-2020
Tuberculosis Fact Sheet—
Alameda County, 2020
CLINICAL CHARACTERISTICS
Of all 2020 TB cases, 71% had pulmonary involvement
and 29% were extrapulmonary only (Table 2). Of all pul-
monary cases, a majority (58%) were acid-fast bacilli
(AFB) smear-negative and 61% did not have evidence of
cavitary disease on chest radiography. No 2020 TB cases
were co-infected with HIV. The most common comor-
bidity was diabetes (34%).
DRUG RESISTANCE
A similar proportion of drug-resistant isolates were iden-
tified among culture-positive cases in 2020 and 2019
(14% and 13%, respectively). During 2020, all 11 TB
cases resistant to any TB treatment drug were resistant
to at least one of the first-line TB medications (i.e., iso-
niazid, rifampin, ethambutol or pyrazinamide). Of all TB
cases with drug susceptibility tests reported, 8 cases
(10%) were resistant to isoniazid only, and 2 (3%) were
resistant to pyrazinamide only. Alameda County had one
multidrug resistant TB case.
DIAGNOSTIC TESTING
Among 2020 TB cases with any pulmonary disease who
had a sputum smear performed, 85% received a nucleic
acid amplification (NAA) test at diagnosis, a higher pro-
portion than among 2019 cases (69%). Similar to 2019,
more 2020 cases with positive sputum AFB smears re-
ceived NAA tests compared to patients with negative
sputum AFB smears (93% and 80%, respectively); a larg-
er proportion of 2020 cases with negative sputum AFB
smears received a NAA test compared to 2019 (79%
and 47%, 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 — A l a m e d a C o u n t y , 2 0 2 0
1100 San Leandro Blvd, Third Floor, San Leandro, CA 94577
Phone: (510) 667-3096 | Fax: (510) 273-3916
http://www.acphd.org/tb.aspx
Last updated March 22, 2021
For questions or additional information, contact:
Alameda County Public Health Department
Tuberculosis Control Section
TB remains an important public health problem in Ala-
meda County. The reduction in TB cases and rates in
Alameda County are consistent with findings in other
California counties and with statewide data. Although the
cause for the reduction in TB cases and rates is un-
known, it is possible that the Coronvavirus disease 2019
pandemic may have impacted the number of patients
who presented for care and were diagnosed with TB. A large proportion of Alameda County TB cases continue to oc-
cur 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 or
more years 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 con-
trol 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, Alameda
County, 2016-2020