The authors have declared that no competing interests exist.
Conceived and designed the experiments: MHG EQ. Performed the experiments: YGM AZGG MC CC. Analyzed the data: AJ MHG EQ. Contributed reagents/materials/analysis tools: PdM TP MHP AT. Wrote the paper: MHG.
Individuals at risk of (H1N1) influenza A infection are recommended to receive vaccination. Chronic hepatitis C (CHC) patients receiving treatment might be at a higher risk of respiratory bacterial infections after influenza infection. However, there are no observational studies evaluating the immunogenicity, tolerance and acceptance of 2009 influenza A vaccine in CHC patients.
We evaluated the immunogenicity of influenza A vaccine (Pandemrix®) by using the hemagglutination inhibition (HI) titers method in a well defined cohort of CHC patients receiving or not receiving pegylated-interferon and ribavirin, and compared it with healthy subjects (controls). A group of patients with inflammatory bowel disease (IBD) under immunosuppression, thought to have a lower immune response to seasonal influenza vaccine, were also included as a negative control group. In addition, tolerance to injection site reactions and acceptance was assessed by a validated questionnaire (Vaccinees' perception of injection-VAPI-questionnaire).
Of 114 subjects invited to participate, 68% accepted and, after exclusions, 72 were included. Post-vaccination geometric mean titers and seroprotection/seroconversion rates were optimal in CHC patients with ongoing treatment (n = 15; 232, CI95% 46–1166; 93%; 93%), without treatment (n = 10; 226, CI95% 69–743: 100%; 100%) and controls (n = 15;168, CI95% 42–680; 93%; 86%) with no differences between groups (
There appeared to be no differences between CHC patients and healthy controls in serological response and acceptance of (H1N1) influenza vaccination.
Physicians who care for patients with chronic digestive disease were recommended by the World Health Organization to encourage patients to receive the novel (H1N1) influenza A vaccine during the global pandemic of 2009. The recommendations concerned elderly patients (>65 years) and those with chronic medical conditions or immunosuppression
In addition, CHC patients with ongoing pegylated-interferon based therapy may have a lower immunogenic response
Therefore, the present study was conducted to evaluate the (H1N1) influenza A virus vaccine immunogenic response in CHC patients with and without ongoing standard medical treatment and compared it with that of healthy subjects.
Recently, a lower immunogenic response has been found in pediatric patients with inflammatory bowel disease (IBD) under immunosuppression therapy
Patients and a group of healthy volunteer healthcare workers were invited to participate and enrolled after written informed consent was obtained. Approval for the study protocol was obtained from the national Agencia Española del Medicamento y Productos Sanitarios and local ethics committee (Hospital Universitario de Canarias), and the study was conducted in accordance with the principles of the 1975 Declaration of Helsinki.
As standard of care, vaccination against (H1N1) influenza A was offered to adult (≥18 years of age) patients with CHC, referred for hepatitis C virus treatment assessment, and IBD patients receiving immunosuppression therapy during at least 3 months. They were recruited consecutively during outpatient visits at the University Hospital of the Canary Islands between November 2009 and March 2010, and followed during at least 6 months.
We excluded patients who had previously been vaccinated against 2009 (H1N1) influenza A, those with documented (H1N1) influenza A infection, a known allergy to eggs or other components of the vaccine, or pregnancy. Previous seasonal influenza vaccination was not an exclusion criterion. Reasons against vaccination given by patients who refused to participate were also recorded.
Medical records were used to retrieve information on hepatitis C virus regarding virus genotype, viral load and other hematological parameters. In those patients receiving hepatitis C virus treatment, the type of pegylated-interferon, ribavirin dose and sustained virological response (SVR) were recorded. Concerning IBD patients, we also recorded the type of disease and immunosuppression treatment at the time of vaccination (azathioprine/6-mercaptopurine, methotrexate or anti-tumour necrosis factor agents) as well as blood test results.
In patients and healthy volunteer healthcare workers, vaccination was administered by intramuscular injection in the deltoid region of the non-dominant arm with a single (0.5 ml) dose of adjuvanted influenza A (A/California/7/2009 H1N1-vlike strain) 2009 vaccine (Pandemrix®, GlaxoSmithKline, Brentford, United Kingdom). Two blood samples per participant were drawn: one before vaccination and one at least 3 weeks after vaccination (3–13 weeks). Serum was stored at −80°C until measurement of hemagglutination inhibition (HI) titers.
Samples were sent on dry ice to the Department of Clinical Microbiology, Hospital Clínic, Barcelona. All samples were coded and the laboratory was blinded to the identity and clinical details of the subjects.
Influenza-specific antibody levels were measured using HI assay with chicken red blood cells according to the World Health Organization standardized protocol
HI antibody titers were summarized with the criteria conventionally used to assess the immunogenicity of influenza vaccines: geometric mean titer (GMT), geometric mean titer ratio (GMTR), seroprotection rate (proportion with titers ≥1∶40), seroconversion rate (proportion with prevaccination titers <1∶10 and a postvaccination titer ≥1∶40, or a prevaccination titer ≥1∶10, and ≥4-fold increase after vaccination)
To assess how injection site reactions are perceived and how this perception affects acceptance of vaccination and willingness to be vaccinated in the future, a structured, self-administered questionnaire designed for this purpose was given to patients and completed 21 days after vaccination. The vaccinees' perception of injection questionnaire (VAPI questionnaire; with permission of Sanofi Pasteur)
In addition, systemic adverse events commonly associated with influenza vaccine were recorded (fever, malaise, nausea/vomiting, diarrhea, headache, myalgia/arthralgia, irritability and somnolence) occurring within 21 days and serious adverse events or death within 6 months of vaccination.
The baseline and post-vaccination GMT and GMTR of HI antibody titers were obtained for each group. After verifying normal distribution of the data with Kolgomorov-Smirnoff test, Log HA antibody titers were compared using ANOVA, and post-hoc comparisons were carried out with Tukeýs HSD test. HI antibody titers below 1∶10 were assigned a value of 1∶5 for the purposes of calculations.
Qualitative data are expressed as frequencies and percentages. The proportions of seroprotection, seroconversion and SVR rates were compared between groups by Jonckheere-Terpstra test. After verifying normal distribution of the data with Kolgomorov-Smirnoff test, the mean scores of VAPI questionnaire dimensions were compared using ANOVA and post-hoc comparisons were carried out with Tukeýs HSD test or Kruskall-Wallis test when appropriate.
Statistical analysis was performed using the SPSS 15.0 for Windows statistical package (SPSS Inc., Chicago, IL) and StatXact-5.0.3 (Cytel CO, MA). Differences with a
One hundred and fourteen patients (aged 41.3±11.4 years, 48% female) were asked to participate in the study. Thirty seven patients (32%) refused to participate; the most common reasons for refusing the (H1N1) influenza A vaccine are shown in
CHC with ongoing treatment, n (%) | CHC without treatment, n (%) | IBD patients, n (%) | |
|
1 (100) | 2(33.3) | 8 (26.7) |
|
0 | 2(33.3) | 6 (20) |
|
0 | 2(33.3) | 3 (10) |
|
0 | 0 | 13 (43.3) |
CHC, chronic hepatitis C; IBD, inflammatory bowel disease.
CHC with ongoing treatment (n = 15) | CHC without treatment (n = 10) | IBD patients (n = 32) | Controls (n = 15) | |
4 (27) | 3 (30) | 17 (53) | 11(73) | |
|
47.4±9.5 | 42.4±10.9 | 36.3±9.6 | 38.8±10.5 |
|
23.4±3.5 | 23.9±3.2 | 24.9±5.0 | 22.0±2.9 |
|
44408±154991 | 1486684±1866724 | - | - |
|
11 (73) | 9 (90) | - | - |
|
- | - | 27 (84) | - |
|
||||
|
- | - | 29 (91) | - |
|
- | - | 3 (9) | - |
|
- | - | 15 (47) | - |
|
||||
|
4.0±2.2 | 7.1±1.7 | 6.2±1.6 | - |
|
2.3±1.4 | 3.4±1.4 | 3.9±1.2 | - |
|
1.1±0.6 | 2.9±0.9 | 1.7±0.9 | - |
|
39.3±4.0 | 44.0±3.0 | 40.5±4.4 | - |
|
159±54 | 207±61 | 264±117 | - |
|
||||
|
30±14 | 112±112 | 23±11 | - |
|
29±21 | 201±256 | 20±16 | - |
CHC, chronic hepatitis C; IBD, inflammatory bowel disease; BMI, Body mass index; AST, aspartate aminotransferase; ALT, alanine aminotransferase.
Mean ± standard deviation.
Fifteen healthy individuals also took part in the study and blood samples were collected.
Regarding the grade of fibrosis in CHC patients, although liver biopsies were only available in four CHC patients with ongoing treatment during vaccination (METAVIR score A1F2, A1F1, A2F3 and A1F1) and two CHC patients not receiving treatment (METAVIR score A2F4, in both), the rest of the patients did not have biochemical (low albumin or prothrombin time, and high bilirubin) or ultrasonographic (liver surface nodularity, parenchymal nodularity, or atrophy of the right lobe) signs of cirrhosis. In addition, noninvasive tests to predict liver fibrosis such as Forns index of fibrosis
Blood samples were available in 67 subjects (5 patients did not have baseline serum).
The global median time between baseline and post-vaccination serum sampling during follow-up was 6 weeks (range 3–13). There were no differences between a) controls [4 (range 4–11)] and CHC group [5 (4–11)];
At baseline, antibodies against the vaccine strain were detected (titer ≥1∶10, but only one higher than 1∶40) in 11 subjects (CHC patients with ongoing treatment, n = 3; CHC patients without treatment, n = 2; IBD group, n = 4 and controls, n = 2).
The overall post-vaccination GMT was 124 (95% CI 25–619), representing a 17.9-fold increase from the pre-vaccination level. The post-vaccination GMT was higher in the group of CHC patients than in the IBD patients (229, 95% CI 55 to 957 vs. 60, 95% CI 12 to 307;
CHC with ongoing treatment (n = 15) | CHC without treatment (n = 10) | IBD patients (n = 27) | Controls (n = 15) | |
|
232 (46–116) | 226 (69–743) |
60 (12–307)* | 168 (42–680) |
|
43 (10–180) | 32 (7–137) |
15 (4–64)‡ | 24 (7–78) |
|
14/15, (93.3) | 10/10, (100) | 18/27, (66.7)¶ | 14/15, (93.3) |
|
14/15, (93.3) | 10/10, (100) | 15/26, (66.7) |
6/7, (85.7) |
CHC, chronic hepatitis C; IBD, inflammatory bowel disease; GMT, Geometric mean titer (IC 95%); GMTR, Geometric mean titer ratio (IC 95%); Seroprotection, n (%); Seroconversion, n (%).
One IBD patient and 4 control subjects did not have pre-vaccination serum sample for GMTR calculation.
The overall proportion with seroprotection and seroconversion was not different between CHC groups and controls (
IBD patients on a single immunosuppressive agent had a similar response rate to those on combined immunosuppression (seroprotection: 10/14, 71.4% vs. 8/13, 61.5%,
The majority of consenting patients completed the VAPI questionnaire (83%,
CHC with ongoing treatment (n = 14) | CHC without treatment (n = 9) | IBD patients (n = 24) | ||
|
2.9±1.4 |
1.7±0.8 | 2.0±1.0 | 0.02 |
|
3.3±1.3 |
1.9±1.1 | 2.0±1.0 | <0.01 |
|
2.3±1.5 | 1.4±1.0 | 1.7±1.3 | 0.16 |
|
6 (43) | 1 (11) | 4 (18) | 0.14 |
|
0 (0) | 0 (0) | 1 (4) | 0.58 |
|
3(21) | 3 (30) | 4 (18) | 0.75 |
|
3 (21) | 2 (20) | 5 (23) | 0.98 |
|
5 (36)/3 (21)/6 (43) | 8 (89)/0 (0)/1 (11) | 14 (64)/4 (18)/4 (18) | 0.11 |
CHC, chronic hepatitis C; IBD, inflammatory bowel disease.
One patient in each CHC group and 8 IBD patients did not complete the questionnaire.
How the patient was bothered by pain, redness, swelling, itching, hardening, bruising at the vaccination site.
Mean ± standard deviation.
Other systemic adverse events specifically assessed (fever, malaise, nausea/vomiting, diarrhea, headache, myalgia/arthralgia, irritability and somnolence) were not different between the groups (
CHC with ongoing treatment (n = 14) | CHC without treatment (n = 9) | IBD patients (n = 24) | ||
|
1 (7) | 0 (0) | 0 (0) | 0.30 |
|
2 (14) | 1 (11) | 2 (8) | 0.23 |
|
0 (0) | 0 (0) | 1 (4) | 0.61 |
|
1 (7) | 0 (0) | 2 (8) | 0.67 |
|
1 (7) | 0 (0) | 1 (4) | 0.68 |
|
2 (14) | 0 (0) | 3 (12) | 0.50 |
|
1 (7) | 0 (0) | 3 (12) | 0.50 |
|
3 (21) | 0 (0) | 1 (4) | 0.11 |
CHC, chronic hepatitis C; IBD, inflammatory bowel disease.
One patient in each CHC group and 8 IBD patients did not complete the questionnaire.
No deaths or serious vaccine-related adverse events were reported during follow-up.
Only one CHC patient with ongoing treatment (with post-vaccination seroprotection) reported symptoms of respiratory disease, although influenza A infection was not confirmed by laboratory tests.
Regarding the impact of influenza vaccination on SVR, no significant differences were found between CHC patients receiving standard medical care during vaccination (n = 15) compared to those treated after vaccination (n = 8). In addition, viral load, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values were not different 6 months after the end of treatment (
CHC with ongoing treatment (n = 15) | CHC treated after vaccination (n = 8) | ||
|
12 (80) | 4 (50) | 0.13 |
|
113±41 | 144±38 | 0.09 |
|
960±155 | 1000±185 | 0.58 |
|
7/15 (46.7) | 5/8 (62.5) | 0.67 |
|
578797± |
128152± |
0.59 |
|
33± |
34± |
0.63 |
|
35± |
36± |
0.72 |
5.36±1.5 | 5.41±1.8 | 0.89 | |
|
0.75± |
|
0.16 |
|
1.82± |
|
0.26 |
CHC, chronic hepatitis C; SVR, sustained virological response; AST, aspartate aminotransferase; ALT, alanine aminotransferase; APRI, AST to platelet ratio index.
Mean ± standard deviation.
Influenza virus infection can cause severe illness and mortality in high risk patients. Annual immunization is highly recommended in elderly subjects and adults with chronic medical conditions or immunosuppression, in order to decrease attributable morbidity and mortality. These recommendations were extended to the pandemic 2009 novel (H1N1) influenza A virus
The infection rate among non-cirrhotic CHC patient receiving current antiviral treatment is 5–30%. This high incidence of infections has been associated to neutrophil impairment due to pegylated-interferon
Regarding CHC patients and influenza vaccination, limited information is available and mostly related to advanced cirrhotic or liver transplant patients
To our knowledge this is the first study to evaluate the immunogenicity, and perceived tolerance of the pandemic 2009 (H1N1) influenza A vaccine in a well defined cohort of CHC patients. Our findings are useful from the opportunistic point of view, taking into account the naive condition of our population to this novel virus strain, which reduces cross-reactive antibodies that may complicate the interpretation of the immunogenic response. Thus, our results may be relevant for any future pandemic caused by a similar virus.
A limitation of our study is the sample size which does not allow us to draw conclusions on vaccine efficacy or effectiveness based on percentage reduction of attack rates (number of new cases during the exposure period divided by the number of people in the population who could catch the disease). On the other hand, clinical attack rate was lower than that predicted by the authorities (20–40% estimated by mathematical modeling conducted in the southern hemisphere), and available data clearly indicate that the clinical protection provided by influenza vaccines is closely correlated with their immunogenicity
Several factors may affect immune response including concurrent use of medications, in particular drugs influencing immune function such as immunosuppression and interferon based therapies
Finally, we investigated the tolerance of the influenza vaccine. Despite the fact that subjects receiving adjuvanted vaccines tended to show more adverse effects
Influenza vaccination apparently did not influence the CHC therapy response. Both groups had similar prognostic factors of favorable outcome after treatment, although caution should again be exercised considering our small sample size. CHC and influenza has aroused interest because of T cell response cross reactivity of a hepatitis C virus epitope (NS3-1073) and influenza A epitope (NA-231), which may theoretically contribute to viral clearance
In conclusion, in our cohort there appeared to be no differences between CHC patients and healthy controls in serological response and acceptance of (H1N1) influenza vaccination.
We thank the participants who volunteered for the study, nurses from the Endoscopy Unit for blood extractions; Beatriz Abrante for her work in coordinating the delivery of samples for measurement of HA and Fundación para la Investigación Biomédica Rafael y Clavijo for editorial support. The VAPI questionnaire is protected by copyright with all rights reserved by Sanofi Pasteur and was used with permission.