Systemic sclerosis (SSc) is a rare autoimmune inflammatory rheumatic disease. Vaccines represent one of the safest and most effective means of disease control.
During the cold months of the year, up to 20% of the overall population can be infected by seasonal Influenza [34][27]. Influenza vaccination is strongly recommended in the majority of patients affected by autoimmune inflammatory rheumatic diseases AIIRD [35][28]. AIIRD are frequently complicated with infections, factors that weigh on the burden of these chronic diseases [36][29]. These conditions involve a higher risk of contracting influenza [37,38][30][31] and also a higher risk of influenza-related complications compared with the general population [39][32].
Data on incidence and prevalence of HAV infection in patients with systemic sclerosis are still lacking. Hepatitis A is a vaccine-preventable disease, and vaccination against HAV with inactivated virus should be offered to all patients considered at risk of contracting hepatitis A; such risk includes: HAV-seronegative patients travelling to or resident in endemic areas; patients having sexual behaviors at high risk of infection; patients having close contact with infected subjects and all patients with chronic liver disease, which correlates with a much more severe infection [94][41]. Regarding HAV vaccination efficacy, data on systemic sclerosis (SSc) are still lacking; there seems to be a strong correlation between serum antibody concentration and seroprotection. Probably, as suggested in some studies on rheumatoid arthritis (RA) and on patients on immunosuppressive drugs, a single dose of HAV vaccine could not be enough to obtain sufficient seroprotection against infection [95][42]. Therefore, a second booster after 6 months and determination of antibody titers is recommended [96][43].
Prevention is preferable to treatment. It is well known that herpes zoster is one of the most common viral opportunistic infections in patients suffering from autoimmune diseases, particularly patients with inflammatory myositis, SLE, RA, and inflammatory bowel disease, due also to the use of immunosuppressive drugs (glucocorticoids, DMARDs, biologic DMARDs, and targeted synthetic DMARDs) that further increase the risk of infection [98,111,112,113][52][53][54][55]. The guidelines for RA treatment recommend administering vaccination prior to initiating DMARD or biologic in patients who are 50 years old or more. Very little is known about incidence and prevalence of herpes zoster in patients with SSc, but some cohort studies have demonstrated that these patients also have a higher incidence rate of infection than general population [110][56]. Administration of a live-attenuated HZ vaccine (Zostavax) reduces the risk of HZ among immunocompetent individuals 50 years old and older, but it is not indicated in immunocompromised patients, who could develop a primary varicella infection [111][53]. Current guidelines suggest administration of a live-attenuated vaccine in patients with autoimmune disease who are considered at high risk, at least 4 weeks before starting an immunosuppressive drug. Moreover, in order to avoid a primary varicella infection, evaluation of serostatus may be considered before the administration [86][57]. A new non-live recombinant subunit adjuvant zoster vaccine, called Shingrix, is now available in some European countries, and it may be a candidate to replace the live-attenuated vaccine, avoiding the risk of iatrogenic infection. Furthermore, comparative studies have demonstrated a better safety profile and higher efficacy of Shingrix than the live-attenuated vaccine [112][54].
The Italian National Vaccine Plan proposes the administration of three doses of the anti-meningococcal B vaccine in the first year of life, whereas anti-meningococcal C vaccine or a dose of tetravalent vaccine is recommended between 13 and 15 months. One dose of tetravalent anti-meningococcal vaccine is then administered in adolescence both to those who did not get vaccinated with MenC or Mcv4 in childhood and to those who have already received a dose, since the immunoprotection is linked to a high antibody titer, which tends to decrease over time [67][58].
The tetravalent vaccine is recommended for all travelers going to countries where vaccine serotypes are present, such as the countries of sub-Saharan Africa. According to the Italian National Vaccine Plan, the meningococcal vaccination is strongly suggested in subjects who are considered at risk due to the presence of particular conditions: hemoglobinopathies, functional or anatomic asplenia, candidates for splenectomy, congenital or acquired immunosuppression conditions, diabetes mellitus, renal/adrenal insufficiency, HIV infection, severe chronic liver disease, cerebrovascular fluid leakage from trauma or surgery, congenital complement, Toll-like receptor 4 and properdin defects, and finally also household members of subjects with the conditions listed above. The recommendations for the administration of vaccines to scleroderma patients are the same as those identified for the entire population with systemic autoimmune diseases. The latest recommendations on vaccination in patients with autoimmune inflammatory rheumatic disease made by European League Against Rheumatism (EULAR) in 2019 do not suggest clear indications for anti-meningococcal vaccination since literature in this field is rather limited [115][59].
Hib vaccination is an inactivated and conjugated vaccine administered intramuscularly for the prevention of Haemophilus influenzae type B infections. Since its introduction, the annual incidence was reduced by 99% in the US [118][60]. In Italy, the National Vaccine Plan schedules the immunization against type B Haemophilus influenzae during the first year (3rd, 5th, 11th month) of every infant’s life through the administration of a “combined” hexavalent vaccine, that contains six vaccines (diphtheria–tetanus–pertussis–polio–hepatitis B, and Haemophilus influenzae) in one syringe. Moreover, according to the National Plan, Hib vaccination is strongly recommended, if not previously done, in the following pathological conditions: functional or anatomic asplenia, candidates for splenectomy, congenital or acquired immunosuppression conditions, complement deficiency, subjects receiving bone marrow transplantation or awaiting solid organ transplantation, subjects undergoing chemotherapy or radiotherapy for the treatment of malignant neoplasms, and cochlear implant carriers [67][58]. The recommendations for the administration of vaccines to scleroderma patients are the same as those identified for patients with systemic autoimmune diseases.
Overall, HPV vaccination has a favorable safety profile. Syncope, headache, and injection site reactions are the most commonly reported adverse events. Serious adverse events, such as adverse pregnancy outcomes, neurological disorders (including Guillain–Barré Syndrome and multiple sclerosis), anaphylaxis, venous thromboembolism, and stroke, are not associated with HPV vaccination. The immunogenicity and safety of HPV vaccine in connective tissue diseases (CTDs) has mostly been evaluated in patients with SLE. Overall, the immunogenicity of the HPV vaccine is similar in patients with SLE and controls, without significant safety concerns. Notably, vaccination does not appear to induce disease flares [138][61]. The recently issued EULAR guidelines state that patients with autoimmune diseases should receive HPV vaccination in accordance with recommendations for the general population. Immunogenicity and safety data of HPV vaccine in SSc patients have not been reported. Of note, after the marketing of quadrivalent HPV vaccine the adverse events reporting system recorded several new diagnoses of autoimmune diseases, including SSc and mixed connective tissue diseases. For this reason, concerns regarding the possible induction of new-onset autoimmune disease by HPV vaccine have been raised. These claims are mostly based on case reports and case series [139,140,141][62][63][64]. Conversely, properly designed longitudinal studies have failed to show an association between quadrivalent HPV vaccine and increased incidence of new-onset autoimmune disease [142][65]. With regard to SSc, in a large longitudinal observational study using administrative databases conducted in France, the incidence of SSc did not differ between young girls exposed to HPV vaccine against those non-exposed (OR 0.70, 95% IC 0.35–1.39), after a median follow-up of 33 months [143][66]. Several other studies confirmed the absence of an association between HPV vaccination and connective tissue diseases, even in subjects with pre-existing autoimmune diseases [144][67].
Although no studies directly assessed the efficacy and safety of DTaP/Tdap/Td vaccination in SSc patients, the EULAR guidelines state that patients with autoimmune diseases should receive toxoid tetanus vaccination in accordance with recommendations for the general population. Overall, patients with RA and SLE showed a good immunogenicity for tetanus toxoid vaccination, comparable with healthy subjects, even if treated with immunosuppressants such as rituximab (RTX) [154][68]. However, the efficacy of Td vaccination is assumed to be decreased upon RTX, based on data extrapolated from other vaccines [155][69]. Indeed, a more recent multicenter cohort study conducted in Switzerland confirmed that tetanus booster vaccination is safe and immunogenic (up to 98% of the subjects) in patients with a variety of rheumatic diseases (including RA, spondyloarthrithis, and vasculitides), whereas diphtheria vaccination may be less immunogenic (73%). In these patients, antibody response appears to be correlated with immunosuppressive therapy, particular grade of immunosuppression, more important with RTX and methotrexate, rather than the underlying autoimmune disease. Importantly, no new safety issues were observed compared with the general population [156][70].
The travel should be planned in advance, in order to be scheduled when the disease activity is as low as possible, and the vaccines should be administered while taking the lowest dose of immune suppressant therapy. The aim is to keep the immunogenicity of the vaccines high and to make the patient less susceptible to infections when reaching the destination country.
Live attenuated vaccines (e.g., yellow fever) must be avoided in patients taking immune suppressant therapy.
We encourage patients to seek the advice of their own general practitioner or specialist to assess the disease activity and damage and to schedule with them the timing of tapering the immune suppressant therapy (if the disease course allows doing this). This should be done at least two months prior to departure. Moreover, the physician should help the patient find all the needed information about the specific infectious risk in the country of destination, the general precautions to be taken when traveling abroad, and the specific vaccination requirements demanded by the local governments. The sources of information are available on the WHO institutional site and from the patient’s own country health or foreign office. Patients should also check with their general practitioner with regard to their own vaccinal certificate to assess whether they have received the appropriate vaccinations and to assess the need for integrations.