A pair of new studies highlight opportunities to reduce the burden of vaccine-preventable infectious diseases among immigrants in the United States, with one revealing fairly high rates of influenza, mumps, and hepatitis A in immigration detention centers and the other finding that only 28.0% of immigrant and refugee adults have completed their tetanus and diphtheria vaccine series.
Flu most prevalent
The first study, a case series led by a University of Minnesota researcher, was conducted at 20 US Immigration and Customs Enforcement (ICE) detention facilities from January 2019 through October 2023 and published yesterday in JAMA Network Open. The aim was to assess the burden and transmission patterns of flu, mumps, and hepatitis A among detainees.
"Suboptimal immunization rates in this population are compounded by limited baseline vaccination data; multiple outbreaks (notably for measles) and preventable infection-related deaths have been reported, including of children," the study authors wrote. "Contributing factors include crowding, suboptimal sanitation, limited health care access, poor ventilation, and inconsistent diagnostic practices."
In addition, except for COVID-19, there are no US detention standards for vaccinations, and the only mandated infectious-disease screening is for tuberculosis.
The researchers found a high prevalence of flu (2,035 cases), mumps (252), and hepatitis A (486), with multiple facility outbreaks and varying seasonality, which they said reflects the risk profiles for respiratory and intestinal infectious diseases of people entering detention. One case each of measles, typhoid, and tetanus were also reported. Men accounted for 79.8% of cases.
In total, 1,739 flu infections across 79 outbreaks (average duration, 2.5 months) in 15 facilities were noted. The average monthly facility flu case rate was 17.3 per 100,000 people, which was lower than national rates. Flu case rates peaked in December (average, 59.4 per 100,000 people), reaching their nadir in September (average, 6.1 per 100,000 people), similar to national patterns. The average patient age was 33.1 years, and most were from Central America.
The ICE center hardest-hit by a flu outbreak was the Port Isabel Service Processing Center in Texas, which in December 2021 recorded 720.0 flu cases per 100,000 person-months.
Decongregation, crowding reduction, vaccination programs key
For mumps, 252 cases were documented, with a monthly average of 4.3 cases. The average monthly case rate per facility was 1.5 per 100,000 people, with infections peaking in June (3.1 cases per 100,000 people) and reaching a low in February (0.1 cases per 100,000 people).
Decongregation, control of facility crowding, and vaccination programs are recommended approaches to reduce transmission risks for incarcerated migrants and facility employees.
Sixteen mumps outbreaks occurred in eight facilities and involved 177 infections lasting an average of 1.8 months. The average patient age was 34.3 years, and most were from Central America and the Caribbean, most notably Honduras (28.2% of cases), Cuba (13.1%), and Guatemala (13.1%).
For hepatitis A, 486 cases were reported, with an average of 8.4 infections per month. The average monthly case rate per facility was 6.0 per 100,000 people. July saw the highest average case rate, at 13.8 cases per 100,000 people, and infections bottomed out in November (2.3 cases per 100,000). There were 33 outbreaks across 11 facilities involving 158 cases with an average duration of 1.2 months. The average patient age was 39.2 years, and most were from Central America, notably Honduras (11.1%), Guatemala (10.1%), and Mexico (8.8%).
"In this case series study, we found that vaccine-preventable disease risk has increased in ICE detention facilities over time, with high variability across facilities, suggesting the potential quality-improvement benefits of reviewing compliance with IHSC mandates," the researchers wrote. "On the basis of these findings, decongregation, control of facility crowding, and vaccination programs are recommended approaches to reduce transmission risks for incarcerated migrants and facility employees."
"Funding for vaccine-preventable infection programs will support the critical work of IHSC [ICE Health Service Corps] to protect the health of detained migrants, ICE employees, and the broader US population," they concluded.
Tetanus, diphtheria rare in US
For the second study, a team led by a Denver Health and Hospital Authority researcher compared documented completions of the three-dose tetanus/diphtheria vaccine series and recommended boosters with electronic health record (EHR)–generated recommendations for immigrants and refugees seen for primary care at three US healthcare systems from 2017 to 2022. The systems were located in Colorado, Minnesota, and Pennsylvania.
Most electronic health record (EHR)-generated recommendations only advise tetanus/diphtheria vaccines every 10 years for persons ≥18 years.
They also compared up-to-date tetanus/diphtheria vaccination rates in this population with World Health Organization (WHO) estimates of childhood three-dose diphtheria/tetanus/pertussis coverage by country of birth and examined whether immigrants and refugees without documented series completion received an EHR-generated recommendation to be vaccinated.
Participants were originally from countries with historically low tetanus/diphtheria/pertussis childhood vaccination coverage. Tetanus and diphtheria infections are rare in the United States, but the authors noted the importance of adequate vaccination.
"Compared with U.S.-born persons, immigrant and refugee adults have lower completion rates for tetanus/diphtheria vaccination series," the authors wrote. "However, most electronic health record (EHR)-generated recommendations only advise tetanus/diphtheria vaccines every 10 years for persons ≥18 years."
The findings were published yesterday in Vaccine.
EHR identified only 34% as overdue
The EHR documented completed diphtheria/tetanus vaccine series in 28% of 50,829 adult immigrant and refugee patients by December 31, 2023. Among the 36,612 adults without such documentation, the EHR identified only 34% as overdue for the vaccine.
Recognizing variations in childhood vaccination coverage by country of birth and confirming prior vaccination are key to improving immunization among adult immigrants and refugees.
Coverage was highest among patients aged 18 to 24 years (41.6%) and lowest among those 65 and older (21.2%). The percentage of women who were up to date with diphtheria/tetanus vaccination was a bit higher than that of men (31.1% vs 23.4%). Among those with at least six primary care visits, 36.3% were current, compared with 12.6% with one or no visits.
"EHR algorithms may fail to identify those lacking documentation of a primary series," the researchers concluded. "Recognizing variations in childhood vaccination coverage by country of birth and confirming prior vaccination are key to improving immunization among adult immigrants and refugees."
