台南地區供膳作業人員週期性體檢A型肝炎血清偵測結果之分析

Seroprevalence of Hepatitis A Marker among Food Handlers Receiving Periodical Health Examination in Tainan Area

目的：台灣近數十年來因環境衛生改善A型肝炎盛行率逐年降低，1982年以後出生者大多無保護性抗體。供膳作業人員若感染急性A型肝炎，可能經由其製備之食物傳播造成A型肝炎群聚感染。本研究目的在探討2019-2021年於台灣南部某醫院進行週期性體檢之供膳作業人員A型肝炎血清偵測結果分析。

方法：本研究採用化學冷光微粒免疫分析法Chemiluminescent Microparticle Immunoassay (CMIA)測定檢體，定義anti-HAV IgM Signal/Cutoff (S/CO) ≥1.2為陽性、0.8≤S/CO<1.2為邊緣陽性、S/CO<0.8為陰性。並進一步將陽性及邊緣陽性定義為anti-HAV IgM異常（IgM異常）。將個案年齡分為三組：20歲以下、21-40歲及41歲以上。進行羅吉斯迴歸分析性別及年齡分組與IgM異常之相關性。

結果：2019-2021年共收案4,798件anti-HAV IgM檢體，其中供膳體檢佔4,532件(94%)。供膳體檢4,532件中，陽性12件(0.3%)，邊緣陽性27件(0.6%)。IgM異常者以女性及41歲以上組較多（女性30件 vs. 男性9件 [p=0.012]；41歲以上組31件 vs. 21-40歲組8件 [p<0.001]）。20歲以下組243人檢體皆為陰性。羅吉斯迴歸分析發現女性(AOR 2.66 [CI 1.26-5.63])及41歲以上組(AOR 5.23 [CI 2.40-11.42])是IgM異常的獨立影響因子。在IgM異常者之次分析中，檢體呈邊緣陽性之個案肝指數皆正常。檢體呈陽性之個案中有兩位肝指數異常，但這兩位供膳作業者並無臨床症狀且後續病毒檢測(HAV RT-PCR)皆為陰性，排除急性A型肝炎感染。

結論：自2019至2021年週期性供膳作業人員體檢anti-HAV IgM篩檢陽性率為0.9%，但絕大多數排除急性A型肝炎。其中女性及41歲以上者較易有偽陽性之情形。

 

Purpose: In Taiwan, the prevalence of hepatitis A has decreased since 1982 thanks to improved sanitation. Most of the citizens born after 1982 do not have protective antibodies against hepatitis A. Protection is of crucial importance for food handlers as hepatitis A in this population cause cluster infection. The study aims to evaluate the seroprevalence of hepatitis A among food handlers receiving periodical health examinations during the period from 2019 to 2021 in our hospital in Tainan.

Method: We collected 4,798 anti-HAV IgM specimens during the study period, of 4,532 specimens (94%) were from food handlers receiving health examinations. Chemiluminescent microparticle immunoassay (CMIA) method was used to analyze anti-HAV IgM. We defined anti-HAV IgM signal/cutoff (S/CO)≥1.2 as positive, 0.8≤S/CO<1.2 as borderline, and S/CO<0.8 as negative. Positive and borderline results were further defined as abnormal anti-HAV IgM. We separated the participants into 3 age groups, <20 years old; 21-40 years old, and >41 years old. Multivariate logistic regression model was applied to evaluate the association between sex, age groups, and abnormal anti-HAV IgM.

Results: Among the 4,532 anti-HAV IgM specimens, 12 positive results (0.3%) and 27 borderline results (0.6%) were detected. A greater cases of abnormal anti-HAV IgM was detected in the female group and the >41 years old group (30 in the female group vs. 9 in the male group [p=0.012]; 31 in the >41 years old group vs. 8 in the 21-40 years old group [p<0.001]). There was no abnormal anti-HAV IgM in the <20 years old group. Adjusting for multiple covariates, we found that being female and an aged over 41 years old were independent risk factors for abnormal anti-HAV IgM. Results of subgroup analysis indicated that all subjects in the borderline group had normal liver enzymes. In the positive group, two subjects had abnormal liver enzymes. However, they received HAV RT-PCR and the results were negative, suggesting the absence of acute hepatitis A.

Conclusion: Our survey on anti-HAV IgM among food handlers receiving health examinations during the period from 2019 to 2021 indicated a 0.9% abnormality rate. However, acute hepatitis A was excluded in most of the examined cases. Females and those aged over 41 years old were identified to be more likely to have anti-HAV IgM false positive.