Introduction

Over the past three decades, the prevalence of food allergy (FA) has been increasing in the urbanized world.1–3 In the UK, the frequency of hospital admissions due to food-induced anaphylaxis was 1.2 per 105 individuals in 1998 which doubled to 2.4 per 105 individuals over 14 years.2 In the USA, a recent population-based study showed that 40–48% of children and adults with FA had an allergy to multiple foods.4 In Europe, the point prevalence of self-reported FA was 13.1% and higher than previous estimates.3 Similar trends were seen in the New Zealand, and Australia.2

In Asia, the prevalence of FA is 1.11–7.65%, along with unique food allergy patterns,5 but it has been gradually increasing, with a two-fold increase over the years.6 However, its prevalence among adults has not been adequately explored. The Australian Health Survey found that 1.3% of individuals (in that country) aged 20–45 years have an FA, with peanut (0.4%) and prawn (0.9%) being the most common allergens.2 In Vietnam, a population-based survey of students aged 16–50 years demonstrated a high prevalence of doctor-diagnosed FA (5.7%), with seafood accounting for a significant proportion (2.6%).7 Indeed, seafood allergy (SFA) is more common in Asia than in other countries, which is attributable to the variation in the consumption of triggering foods, dietary habits, cooking patterns, and food sources across regions. Asians consume two-thirds of the world’s seafood production, including species that are not commonly consumed in other countries.8,9

Despite its widespread occurrence, diagnosing and managing SFA remain challenging.10 The consumption of various crustaceans, mollusks, and fish species complicates the identification of the causative food.11,12 Seafood consumption can trigger both IgE-mediated and non-IgE-mediated reactions. A range of adverse reactions can occur following seafood consumption, which can be misdiagnosed as SFA, including scombroid poisoning, toxins, and anisakis infection.11,13 Each seafood species contains multiple isoforms of allergens or cross-reactive allergens. Furthermore, the commercial extracts of seafood used in daily practice for allergic testing contain variable levels of allergens, which may result in overdiagnosis or underdiagnosis Thus, a standard diagnostic approach for SFA is not suitable for all patients. Efforts have been made to elucidate the important seafood allergens, providing a framework for implementing a component-resolved diagnostic strategy.12 In Vietnam, although SFA is common in children aged 2–6 years and in adults, there is a paucity of information related to seafood allergens.7,14,15 Thus, we investigated the prevalence of shellfish and fish allergy, evaluated the characteristics of SFA, and identified the risk factors for severe SFA among university students in an urban city of Vietnam. We selected Ho Chi Minh City (HCMC) because it is the largest and most highly populated city in the country, with a large number of migrants from the surrounding provinces.

Methods Study Design

A cross-sectional, web-based survey was conducted among students aged ≥ 18 years old in HCMC, Vietnam, between December 2021 and July 2022. Based on convenience sampling, three universities were selected, including the University of Medicine and Pharmacy at HCMC, Pham Ngoc Thach University of Medicine, and Tan Tao University. An invitation letter with detailed information about the study was distributed among undergraduate and graduate students of the selected universities regardless of the presence or absence of SFA, and only patients reported SFA would be analyzed. After reading the study description, participants provided consent and agreed to join the study by clicking on the link to the survey. To have participants more likely to consume seafood species in HCMC, we selected the students who have continuously stayed in HCMC for more than one week. This study complies with the Declaration of Helsinki and the study protocol was approved by the Ethics Committee Review Board of the University of Medicine and Pharmacy at HCMC (No: 251/HĐĐĐ-ĐHYD).

Sample Size

The sample size was calculated using the following formula:

where n is the sample size, Z is the statistic corresponding to the level of confidence (95%), p is expected prevalence, and d is the allowable margin of error (0.05).16 As the prevalence of shellfish and fish allergy among individuals with SFA in Vietnam is unknown, we selected a p value of 19% based on a study conducted in the US.17 The minimum sample size was 237. Furthermore, we performed a pilot study to validate the survey among 30 participants.

Survey

The survey involved the administration of a structured questionnaire, which was validated in previous studies among the US and Asian populations.18–20 The first part of the survey included questions related to demographic information (age, sex, household income, educational level), physicians’ diagnosis of allergic disorders (asthma, eczema, and allergic rhinitis), and allergy to peanuts, tree nuts, crustacean shellfish, mollusk, and fish. All participants completed the first part of the survey, whereas only those with a history of allergic reactions to crustaceans, mollusks, or fish completed the second part. In the second part, participants answered specific questions pertaining to shellfish and fish allergy based on the original questionnaire.18–20 The survey and questionnaire were translated from English into Vietnamese. To validate the survey, four independent translators performed forward and backward translations. An expert committee, including allergy specialists, reviewed the translated questionnaires. The seafood species included species originating from Vietnam and approved by the expert committee. The web-based questionnaire was transformed into a hierarchical, web-based survey using TypeformTM. Next, the pilot study was conducted on 30 participants to evaluate the survey before the study. Survey responses were collected anonymously and exported to Microsoft Excel for further analysis. Data were collected anonymously, kept confidential and only accessed by the lead investigator.

Definitions of SFA and Severe SFA

“Convincing SFA” and “probable SFA” were defined according to physician diagnosis and corresponding symptoms and history, as described by Sicherer et al.19 Reactions considered convincing were urticaria/rash, angioedema, dyspnea, itchy mouth, throat tightness, and dizziness/cough with at least one gastrointestinal symptom (vomiting, abdominal pain, diarrhea, and nausea) within 2 h of food intake. The presence of other symptoms was defined as probable SFA. Although allergic testing results were also considered when classifying SFA, most participants had not undergone skin prick testing or food challenge; thus, SFA was defined based on the standardized questionnaire. The participants who did not meet the criteria for convincing or probable SFA were classified as having “self-reported SFA” and excluded from further analysis. SFA severity was defined according to the presence of choking, wheezing/dyspnea, or loss of consciousness, as reported previously.20

Statistical Analysis

We conducted a descriptive study using a survey data. The normality test was checked by Kolmogorov–Smirnov test. The continuous variables were expressed as mean ± SD. The categorical data were displayed as %. Comparison between groups was performed by Student’s t-test or one-way ANOVA for the continuous data or by Pearson’s chi-square or Fisher’s exact test for the categorical variables. The risk factors of severe SFA compared with nonsevere SFA were analyzed by a multivariate logistic regression, calculating the odds ratios (ORs) and 95% confidence interval (CIs). Based on previous studies,14,17 clinical experience, and significant association with the outcome variable, potential covariates were included, such as age, gender, history of asthma, history of anaphylaxis, comorbid peanut/nut allergy, and allergy to ≥ 3 seafood species. The cross-reactivity between species was calculated by Pearson correlation coefficient A P value < 0.05 was considered as statistical significance. All analysis was performed using JASP (v0.16.3), except for multivariate logistic regression was performed by IBM®SPSS® 22.0.

Results Participation Rate and Demographic Characteristics of Participants

The number of individuals surveyed and their demographic characteristics were summarized in Table 1 and Supplementary Figure 1. The survey was administered to 2137 individuals, of whom 1038 agreed to participate (response rate of 48.57%). Among them, 285 had a history of SFA. Supplementary Table 1 presents data collected from 209 participants with convincing SFA (20.13%), 23 with probable SFA (2.22%), and 53 with self-reported SFA (5.11%). Shellfish allergy (18.98%) was more common than fish allergy (3.56%) and comorbid shellfish and fish allergy (2.41%) (Supplementary Table 1).

Table 1 Demographic Characteristics of the Study Subjects

The median age of participants with convincing allergy was 21 years and the male:female ratio was 1:1.90 (Table 1). Most participants had income 2.2–5.0 million VND per month, and half lived in rental housing. There were no significant differences between only shellfish allergy, only fish allergy, and comorbid shellfish and fish allergy groups.

Causative Seafood and Coexisting Allergy Across Seafood Species

We analyzed the cross-reactions following seafood consumption among individuals with convincing allergy. The causative species included various crustaceans (tiger prawns, crabs, tiny shrimps, and lobsters), mollusks (squids, clams, oysters, and snails), and fishes (tuna, mackerel, pompano, and red tilapia) (Supplementary Table 2). Some participants (2.70–5.74%) were unaware of the species that caused allergic symptoms.

Most participants experienced allergic reactions following the consumption of multiple species within the same group of shellfish or fish or between shellfish and fish (Figure 1). Notably, cross-reactivity occurred among the the same group (crustaceans/mollusk/fish) more frequently than between crustaceans and mollusks or fish, with the correlation of cross-reactivity being highest within the same group (all P<0.05).

Figure 1 Coexisting allergy between seafood species among participants with convincing allergy. In each cell, the correlation of subjects who were allergic to each column had comorbid allergy to each row, and in reverse. Correlation was calculated by Pearson correlation coefficient. *P<0.05, **P<0.01.

History of Comorbid Allergic Diseases Among Participants with Convincing Allergy

As shown in Table 2, rash/urticaria was the most common comorbid disorder, followed by allergic rhinitis. Individuals with comorbid shellfish and fish allergy had a significantly higher prevalence of atopic dermatitis, peanut/nut allergy, and other food allergy than individuals with only shellfish allergy (P=0.044, P=0.018, P<0.001, respectively). Almost 10% of participants had a history of anaphylaxis (Table 2).

Table 2 History of Comorbid Allergic Diseases Among Subjects with Convincing Allergy

Age of Onset, Age at First introduction, and Reactions to Seafood Consumption

Most participants with SFA developed their first reactions after 6 years of age, with the highest frequency of reactions reported at ages 11–16 years and 6–10 years among participants with shellfish and fish allergy, respectively (Figure 2). A small number of participants developed SFA at age < 1 year or during adulthood. Furthermore, the ages at first consumption of shellfish and fish were 6–10 years and 11–16 years among participants with shellfish and fish allergy, respectively. Moreover, 6.30–20.30% of participants developed reactions to fish and shellfish during adulthood, respectively. The age of onset positively correlated with the age at first introduction of both shellfish (r=0.715, P<0.001) and fish (r=0.757, P<0.001). In most participants, SFA persisted until adulthood, with 69.19–84% of participants experiencing reactions sometimes or always following shellfish consumption and 33.33–68.00% experiencing reactions following fish consumption. Participants with comorbid shellfish and fish allergy (68.00%) had a higher prevalence of reactions than those with only fish allergy (33.33%) (p < 0.05).

Figure 2 (A) Age of onset of SFA symptoms and (B) age of first introduction of shellfish/fish among convincing allergy subjects. The percentage of subjects who had persistent reactions after (C) shellfish or (D) fish consumption. *P <0.05. P values were calculated by Pearson’s chi-square.

Symptoms Following Seafood Consumption Among Participants with Convincing Allergy

The participants experienced variable symptoms following the consumption of shellfish and fish (Table 3), with mild to moderate symptoms (rash/urticaria, cough, lip/face swelling, itchy throat/mouth, and flush) being the most common. Participants with comorbid shellfish and fish allergy developed cutaneous symptoms (urticaria/rash, lip/face swelling, and eye/eyelid swelling) and upper respiratory tract symptoms (cough, nasal congestion, and runny nose) more frequently than those with shellfish allergy (all p < 0.05). No significant differences were observed between the groups in terms of life-threatening symptoms (choking, wheezing, or shortness of breath, faint, or dizziness, and loss of consciousness).

Table 3 Prevalence of Symptoms Among the Convincing Allergy Group

Behavioral Characteristics of Participants

The participants were asked how they cope with fish and shellfish allergic reactions (Table 4). Almost half of the participants did not seek treatment, whereas a minority of participants underwent allergy testing and visited a physician. Participants with allergy to multiple species of shellfish and fish visited doctors and received steroids and asthmatic medications more commonly than those with shellfish allergy, although the difference was not statistically significant. Only 6.09% subjects with shellfish allergy and 2.70% subjects with fish allergy underwent allergy testing, and none of the participants received prophylactic or injectable epinephrine (data not shown).

Table 4 Characteristics of Behavior Towards Seafood Allergy

Risk Factors of Severe Allergy to Shellfish, Fish, or Other Seafood

Multivariate logistic regression was used to analyze the risk factors of severe SFA. History of asthma, anaphylaxis, comorbid peanut and nut allergy, and allergic reactions to ≥3 seafood allergens were associated with an increased adjusted odds ratio of severe SFA (Table 5) (aOR=4.16, P=0.016; aOR=6.28, P=0.001; aOR=7.72, P=0.012; aOR=3.18, P=0.002). Furthermore, anaphylaxis, comorbid peanut and nut allergy and allergic reactions to ≥3 seafood allergens were predictors of shellfish allergy (aOR=5.87, P=0.002; aOR=8.37, P=0.009; aOR= 5.86, P=0.001). Males were less likely to have severe reactions to seafood than females, although there was no effect of sex on the prevalence of severe shellfish allergy.

Table 5 Multivariate Logistic Regression Analysis of Severe Allergy to Shellfish or Any Seafood

Discussion

This study is the first to evaluate the prevalence of shellfish and fish allergy, as well as the risk factors of severe reactions, in the Vietnamese adult population. Our results confirm that shellfish allergy is more common than fish allergy. The study was conducted in HCMC, one of the largest municipal cities in Vietnam, with a high population density and diverse species transported from the southern provinces of Vietnam. The use of a strict definition used for convincing SFA provided precise estimates of the numbers, demographic information, and clinical manifestations among the adult population. Our findings demonstrate the diverse spectrum of causative seafood and the cross-reactivity between participants with SFA; these provide a useful basis for further studies on molecular seafood allergens. A small proportion of participants developed reactions to both shellfish and fish. More than half of the participants did not seek healthcare, despite persistent reactions to seafood. Moreover, a history of asthma, anaphylaxis, comorbid peanut and nut allergy, and multiple seafood allergy were risk factors for severe symptoms following seafood consumption.

SFA is the most common FA in many Asian countries, and has an increasing prevalence in the US.7,15,21–23 In Europe, the pooled estimates for self-reported lifetime prevalence for fish and shellfish allergy were 1.4% and 0.4%, respectively.24 While in Asia, the prevalence ranged from 0–7.23% for shellfish allergy, and 0–4.59% for fish allergy.9 Our results demonstrate that shellfish allergy (18.98%) was more common than fish allergy (3.56%) among participants with SFA. Notably, a subgroup of patients developed reactions following fish and shellfish consumption (2.41%). In a previous study among Vietnamese adults, the prevalence of self-reported allergy to crustaceans, fish, and mollusk were 6.88%, 3.71%, and 3.09%. We found a similar prevalence of fish allergy and slightly higher prevalence of SFA and shellfish allergy.15 We focused on describing the characteristics of participants with reactions to seafood. Crustacean allergy was more common than mollusk allergy, which is in line with previous studies and can be explained by the higher consumption of crustaceans than mollusks.15,25,26 In Vietnam, the average seafood consumption has been increasing over the years. Although there was no information on the average consumption by species, crustaceans (shrimps, crabs, and sentinel crabs) account for a higher proportion among exported seafood than mollusks.27 Interestingly, the causative seafood species were region-specific and differed from previous reports. For example, a study from Singapore found a high prevalence of reactions to threadfin, salmon, and cod,28 whereas reactions to tuna, mackerel, and pompano were more common in our study. These discrepancies can be explained by the diversity of seafood species and their consumption, as well as differences in the food delicacies between countries.

Increasing evidence suggests the existence of cross-reactivity between seafood species.10,29,30 Therefore, physicians should evaluate the coexistence of other seafood species among patients with suspected SFA. We found a high prevalence of cross-reactivity between seafood species, with most participants having allergy to multiple species and only a minority having isolated SFA. Prawns were the most common crustaceans causing SFA, in line with previous studies.31,32 Participants with crustacean allergy developed reactions to mollusks (<50%) and fish (0–20%). Furthermore, 15–30% of participants had comorbid reactions to other foods. In a study in the US, 66.2% of adults with SFA had no comorbid allergy,33 whereas another study reported that young adults with shrimp sensitivity developed reactions to multiple shellfish species.30 These findings can be explained by frequent seafood consumption and homologous proteins between foods. Multiple allergenic epitopes of foods can lead to cross-reactivity.34 Shared cross-reactive allergens, such as shellfish tropomyosin and fish parvalbumin, can lead to co-reactions between crustaceans and mollusks as well as low cross-reactivity with fish. As a result, studies of molecular allergens in seafood species from Vietnam are needed. Comorbid reactions should be considered by physicians when providing dietary advice to patient.

There is a paucity of data regarding the age at the time of first reaction to seafood and resolution of allergy with age among the Vietnamese population. Our findings indicate that most SFA events occurred during childhood and adolescence. The persistence of SFA until adulthood was consistent with previous studies.35,36 Our results are in line with studies from the US, which showed that the average age at the time of shellfish diagnosis in adult and pediatric populations was 15.9 years.25 In another survey conducted in Singapore and the Philippines, the age at the time of onset of shellfish allergy was lower (6–10 years) than in our study.18 This may be because the age at the time of first introduction to shellfish and fish was during late childhood (6–10 years) or adulthood in our study.

Cutaneous symptoms were the most common symptoms triggered by seafood consumption in different populations.7,14,18–20,25,28 In our study, the prevalence of severe symptoms was similar to that reported from Singapore and the Philippines19 but higher than that among Vietnamese adults.14 This may be because we focused on participants with SFA, whereas previous studies conducted among Vietnamese adults included participants with all FAs. Shek et al hypothesized that cross-reaction with dust mite allergy contributes to mild cases of shellfish allergy.20 Interestingly, sensitization to house dust mites is common in Vietnam, about 6.3–30.9% in the population and even higher in patients with allergic diseases (49.6–59.8%)37,38 Therefore, it can lead to primary sensitization with dust mite tropomyosin, a panallergen and a major allergen in shellfish and mollusk. Other pan-allergens were highlighted, such as arginine kinase, troponin C, and triosephosphate isomerase, etc. The mentioned proteins also share homology with other invertebrate allergen sources, such as mites, insects, and parasites.39–41 Further studies of SFA should evaluate the cross-reactivity with dust mites in Vietnam.

It is unanticipated that half of the participants did not receive treatment for SFA. Antihistamines were commonly used by all participants for rash/urticaria following seafood consumption. Among participants with shellfish reactions, emergency department visits, hospitalizations, and use of steroids and epinephrine were common. However, most participants did not undergo the oral food challenge test, the gold standard method for the diagnosis of FA, or receive autoinjector epinephrine due to unavailability. These issues make the management of patients with SFA challenging and should be given more attention in the future.

The severity of SFA is affected by the presence of comorbidities and epidemiological factors. Histories of asthma, anaphylaxis, comorbid peanut and nut allergy, and allergy to ≥3 seafood species were associated with increased odds of life-threatening symptoms in any SFA and shellfish allergy. Conversely, male sex was associated with lower odds of severe seafood allergy. In a study from the US, comorbid asthma, peanut, and tree nut allergy and severe FA were associated with increased odds of FA-related emergency department visits and epinephrine prescriptions.17 Female adults are more likely to have FAs than males.14,17 The number of allergenic seafood species is also a strong predictor for severe symptoms and should be recorded during patient consultations.

Several limitations of our study should be considered when interpreting the results. First, SFA was recorded on the basis of symptoms rather than allergic tests. We stratified the participants into convincing allergy, probable allergy, and self-reported allergy based on their history, symptoms, and time of onset, similar to previous studies.18–20 Second, the possibility of selection and recall bias cannot be excluded. This study was performed among university students, who have convenient access to the Internet. To enhance the accuracy of our results, each response was checked twice by two independent researchers, and suspicious responses were removed. Thirdly, the participation rate was less than 50%, and there might be a participation bias for those who had history of shellfish or fish, which led to over-estimation of SFA.

Conclusions

In conclusion, our results enhance understanding of SFA among adults from Vietnam. Shellfish accounted for most cases of SFA, whereas a minority of patients had allergy to both shellfish and fish. The seafood causing reactions differs from other countries’ reports according to local species. Half of the participants did not receive any treatment for SFA. SFA tended to occur late and persisted into adulthood. Female sex, asthma, anaphylaxis, comorbid peanut and nut allergy, and reactions to ≥3 seafood species increased the odds for severe SFA. Our results provide a reference for patient management and highlight the need for further studies.

Acknowledgments

We would like to thank the Module of Scholarly Project, Faculty of Medicine and Student Unions from the participating universities for their support in survey distribution. We also would like to express our thankfulness to Professor Scott H. Sicherer for his advice during the translation and validation of the survey.

Funding

This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 108.02-2020.17.

Disclosure

The authors report no conflicts of interest in this work.

References

1. Peters RL, Krawiec M, Koplin JJ, Santos AF. Update on food allergy. Pediatr Allergy Immunol. 2021;32(4):647–657. doi:10.1111/pai.13443

2. Tang ML, Mullins RJ. Food allergy: is prevalence increasing? J Intern Med. 2017;47(3):256–261. doi:10.1111/imj.13362

3. Spolidoro GCI, Amera YT, Ali MM, et al. Frequency of food allergy in Europe: an updated systematic review and meta-analysis. Allergy. 2023;78(2):351–368. doi:10.1111/all.15560

4. Warren CM, Aktas ON, Manalo LJ, Bartell TR, Gupta RS. The epidemiology of multifood allergy in the United States: a population-based study. Ann Allergy Asthma Immunol. 2023;130(5):637–648.e5. doi:10.1016/j.anai.2022.12.031

5. Lee AJ, Thalayasingam M, Lee BW. Food allergy in Asia: how does it compare? Asia Pacific Allergy. 2013;3(1):3–14. doi:10.5415/apallergy.2013.3.1.3

6. Hu Y, Chen J, Li H. Comparison of food allergy prevalence among Chinese infants in Chongqing, 2009 versus 1999. Pediatr Int. 2010;52(5):820–824. doi:10.1111/j.1442-200X.2010.03166.x

7. Le TTK, Tran TTB, Htm H, Atl V, Lopata AL. Prevalence of food allergy in Vietnam: comparison of web-based with traditional paper-based survey. World Allergy Organ J. 2018;11:16. doi:10.1186/s40413-018-0195-2

8. Hosomi R, Yoshida M, Fukunaga K. Seafood consumption and components for health. Glob J Health Sci. 2012;4(3):72. doi:10.5539/gjhs.v4n3p72

9. Wai CY, Leung NY, Leung AS, Wong GW, Leung TF. Seafood allergy in Asia: geographical specificity and beyond. Front Allergy. 2021;2. doi:10.3389/falgy.2021.676903

10. Davis CM, Gupta RS, Aktas ON, Diaz V, Kamath SD, Lopata AL. Clinical management of seafood allergy. J Allergy Clin Immunol Pract. 2020;8(1):37–44. doi:10.1016/j.jaip.2019.10.019

11. Ruethers T, Taki AC, Johnston EB, et al. Seafood allergy: a comprehensive review of fish and shellfish allergens. Mol Immunol. 2018;100:28–57. doi:10.1016/j.molimm.2018.04.008

12. Tong WS, Yuen AW, Wai CY, Leung NY, Chu KH, Leung PS. Diagnosis of fish and shellfish allergies. J Asthma Allergy. 2018;11:247. doi:10.2147/JAA.S142476

13. Prester L. Seafood allergy, toxicity, and intolerance: a review. J Am Coll Nutr. 2016;35(3):271–283. doi:10.1080/07315724.2015.1014120

14. Le TT, Nguyen DH, Vu AT, Ruethers T, Taki AC, Lopata AL. A cross‐sectional, population‐based study on the prevalence of food allergies among children in two different socio‐economic regions of Vietnam. Pediatr Allergy Immunol. 2019;30(3):348–355. doi:10.1111/pai.13022

15. Le TT, Tran TT, Ho HT, Vu AT, McBryde E, Lopata AL. The predominance of seafood allergy in Vietnamese adults: results from the first population-based questionnaire survey. World Allergy Organ J. 2020;13(3):100102. doi:10.1016/j.waojou.2020.100102

16. Arya R, Antonisamy B, Kumar S. Sample size estimation in prevalence studies. Indian J Pediatr. 2012;79(11):1482–1488. doi:10.1007/s12098-012-0763-3

17. Gupta RS, Warren CM, Smith BM, et al. Prevalence and severity of food allergies among US adults. JAMA network open. 2019;2(1):e185630–e185630. doi:10.1001/jamanetworkopen.2018.5630

18. Shek LP-C, Cabrera-Morales EA, Soh SE, et al. A population-based questionnaire survey on the prevalence of peanut, tree nut, and shellfish allergy in 2 Asian populations. J Allergy Clin Immunol. 2010;126(2):324–331. e7. doi:10.1016/j.jaci.2010.06.003

19. Sicherer SH, Muñoz-Furlong A, Sampson HA. Prevalence of peanut and tree nut allergy in the United States determined by means of a random digit dial telephone survey: a 5-year follow-up study. J Allergy Clin Immunol Pract. 2003;112(6):1203–1207. doi:10.1016/S0091-6749(03)02026-8

20. Connett GJ, Gerez I, Cabrera-Morales EA, et al. A population-based study of fish allergy in the Philippines, Singapore and Thailand. Int Arch Allergy Immunol. 2012;159(4):384–390. doi:10.1159/000338940

21. Verrill L, Bruns R, Luccioli S. Prevalence of self-reported food allergy in U.S. adults: 2001, 2006, and 2010. Allergy Asthma Proc. 2015;36(6):458–467. doi:10.2500/aap.2015.36.3895

22. Wu TC, Tsai TC, Huang CF, et al. Prevalence of food allergy in Taiwan: a questionnaire-based survey. Intern Med J. 2012;42(12):1310–1315. doi:10.1111/j.1445-5994.2012.02820.x

23. Lee S-H, Ban G-Y, Jeong K, et al. A retrospective study of Korean adults with food allergy: differences in phenotypes and causes. Allergy Asthma Immunol Res. 2017;9(6):534–539. doi:10.4168/aair.2017.9.6.534

24. Spolidoro GC, Ali MM, Amera YT, et al. Prevalence estimates of eight big food allergies in Europe: updated systematic review and meta‐analysis. Allergy. 2023;78(9):2361–2417. doi:10.1111/all.15801

25. Wang HT, Warren CM, Gupta RS, Davis CM. Prevalence and characteristics of shellfish allergy in the pediatric population of the United States. J Allergy Clin Immunol Pract. 2020;8(4):1359–1370.e2. doi:10.1016/j.jaip.2019.12.027

26. Moonesinghe H, Mackenzie H, Venter C, et al. Prevalence of fish and shellfish allergy: a systematic review. Ann Allergy Asthma Immunol. 2016;117(3):264–272.e4. doi:10.1016/j.anai.2016.07.015

27. Bank TW Economic impact assessment from commercial analysis of non-compliance with anti-illegal, unreported fishing and unregulated (IUU): the case of Vietnam (Đánh giá tác động kinh tế từ phân tích thương mại của việc không tuân thủ quy định về chống khai thác thủy sản bất hợp pháp, không báo cáo và không theo quy định (IUU): trường hợp Việt Nam). 2021. Available from: https://wtocenter.vn/file/18515/a-trade-based-analysis-of-the-economic-impact-in-vnese.pdf. Accessed March1, 2024.

28. Tan LL, Lee MP, Loh W, Goh A, Goh SH, Chong KW. IgE-mediated fish allergy in Singaporean children. Asian Pac J Allergy Immunol. 2023. doi:10.12932/ap-250722-1417

29. Wu Y, Lu Y, Huang Y, et al. Insight analysis of the cross-sensitization of multiple fish parvalbumins via the Th1/Th2 immunological balance and cytokine release from the perspective of safe consumption of fish. Food Qual Saf. 2022;6:fyac056. doi:10.1093/fqsafe/fyac056

30. Waring NP, Daul CB, deShazo RD, McCants ML, Lehrer SB. Hypersensitivity reactions to ingested crustacea: clinical evaluation and diagnostic studies in shrimp-sensitive individuals. J Allergy Clin Immunol. 1985;76(3):440–445. doi:10.1016/0091-6749(85)90724-9

31. Castillo R, Carrilo T, Blanco C, Quiralte J, Cuevas M. Shellfish hypersensitivity: clinical and immunological characteristics. Allergologia et immunopathologia. 1994;22(2):83–87.

32. Morgan JE, O’Neil CE, Daul CB, Lehrer SB. Species-specific shrimp allergens: RAST and RAST-inhibition studies. J Allergy Clin Immunol. 1989;83(6):1112–1117. doi:10.1016/0091-6749(89)90454-5

33. Khan F, Orson F, Ogawa Y, Parker C, Davis CM. Adult seafood allergy in the texas medical center: a 13-year experience. Allergy Rhinology. 2011;2(2):e71–7. doi:10.2500/ar.2011.2.0019

34. Ayuso R, Sánchez-Garcia S, Lin J, et al. Greater epitope recognition of shrimp allergens by children than by adults suggests that shrimp sensitization decreases with age. J Allergy Clin Immunol. 2010;125(6):1286–1293.e3. doi:10.1016/j.jaci.2010.03.010

35. Lawlis T, Bakonyi S, Williams LT. Food allergy in schools: the importance of government involvement. Nutr Diet. 2017;74(1):82–87. doi:10.1111/1747-0080.12225

36. Jeong K, Lee S. The natural course of IgE-mediated food allergy in children. Clin Exp Pediatr. 2023;66(12):504–511. doi:10.3345/cep.2022.01004

37. Trinh TH, Nguyen PT, Tran TT, Pawankar R, Pham DL. Profile of aeroallergen sensitizations in allergic patients living in southern Vietnam. Front Allergy. 2022;3:1058865. doi:10.3389/falgy.2022.1058865

38. Lâm HT, Ekerljung L, Bjerg A, Văn Tường N, Lundbäck B, Rönmark E. Sensitization to airborne allergens among adults and its impact on allergic symptoms: a population survey in northern Vietnam. Clin Transl Allergy. 2014;4(1):1–9. doi:10.1186/2045-7022-4-6

39. Barre A, Simplicien M, Cassan G, Benoist H, Rougé P. Food allergen families common to different arthropods (mites, insects, crustaceans), mollusks and nematodes: cross-reactivity and potential cross-allergenicity. Revue francaise d’allergologie. 2018;58(8):581–593. doi:10.1016/j.reval.2018.10.008

40. Alsailawi H, Mudhafar M, Mohammed RK, et al. Clinical Implications of Cross-Reactive Shellfish Allergens. J Chem. 2021;15:16–31.

41. Lopata AL, Kleine-Tebbe J, Kamath SD. Allergens and molecular diagnostics of shellfish allergy. Mol Allergy Diagn. 2017;399–414.