Why might dermatology patients be immunocompromised?
The immune system is compromised when an immune response is not as efficient or efficacious as normal.
Dermatology patients may be immunocompromised due to:
- Primary immunodeficiency diseases
- Acquired immunodeficiency such as with human immunodeficiency virus (HIV) infection
- Physiological events, including pregnancy and ageing
- Drug-induced immunosuppression.
Immunisation and drug-induced immunosuppression
Immunosuppression can result in serious bacterial, fungal, and viral infections which may not present with typical clinical features. All patients on immunomodulators should be warned of their increased infection risk and must particularly report exposure to chickenpox or measles. Immunocompromised patients who are unwell should be carefully evaluated and their infections actively treated.
Live viral and bacterial vaccines should not be administered to immunosuppressed patients due to the risk of developing a vaccine infection, and ideally these should be administered before starting immunomodulatory treatment.
- Live oral vaccines — rotavirus, oral (Sabin) polio, typhoid fever
- Live intranasal viral vaccines — influenza
- Live injected viral vaccines — MMR, varicella/zoster, yellow fever, smallpox
- Live injected bacterial vaccines — BCG.
Step 1: Take an immunisation and disease-risk history
An effective immune response can follow natural infection or vaccination/immunisation. Prior to starting any immunomodulatory therapy, the following should be determined:
- Prior immunisations. Each country has its own recommendations which will change with time. Older people may not have received all the vaccines provided by the current schedule.
- History of chickenpox and other vaccine-preventable diseases
- Risk of tuberculosis (TB): for example, family history, residence in or travel to high-risk areas
- Risk of Chagas disease: for example, birth in endemic country, blood transfusion or organ transplant in endemic country
- Risk of COVID-19: for example, travel history, works or lives with worker in high-risk industry.
New Zealand National Immunisation Schedule (2020)
The government-funded immunisation schedule is as follows.
- Diphtheria, whooping cough (pertussis), tetanus (DTaP) at age six weeks, 3 months, 5 months, 4 years, and 11 years. Further diphtheria and tetanus doses are given during pregnancy and at ages 45 and 65 years.
- Polio (IPV) at age 6 weeks, 3 months, 4 months, and 5 months.
- Hepatitis B at age 6 weeks, 3 months, and 5 months.
- Pneumococcus (10-valent PCV) at age 6 weeks, 5 months, and 12 months.
- Haemophilus (Hib-PRP-T) at age 6 weeks, 3 months, 5 months, and 15 months.
- Rotavirus (RV1) at age 6 weeks and 3 months.
- Measles, mumps, rubella (MMR) at age 12 months and 5 months.
- Varicella (chickenpox) at 15 months of age.
- Human papillomavirus (9-valent) at 11–12 years of age.
- Influenza during pregnancy and annually from 65 years of age.
- Herpes zoster (shingles) at 65 years of age.
- Additional vaccines may be included from time to time, such as prevalent meningococcal strains.
Additional unfunded vaccinations that may be recommended prior to travel in endemic areas may include hepatitis A, cholera, typhoid, cholera, rabies, and BCG.
COVID-19 vaccination programs are being rolled out around the world.
Step 2: Perform appropriate tests
- Tuberculin skin test such as Mantoux or PPD
- Interferon-gamma release assay (IGRA) blood test such as QuantiFERON-TB-Gold
- Chest X-ray.
Check varicella, measles, hepatitis A/B/C, HIV, and Chagas serology. There are currently no vaccines for Chagas disease, hepatitis C, or HIV. Treatment for tuberculosis, Chagas disease, hepatitis C, and HIV should be started if required prior to initiating immunomodulating therapies.
Step 3: Vaccinate prior to starting immunomodulatory therapy
At least one month prior to starting immunomodulating therapies, the following immunisations should be given to minimise the risk of preventable infections:
- Give any outstanding vaccinations from the immunisation schedule. Note, the second MMR can be given as early as one month after the first.
- Immunise if not immune (even if previously vaccinated) to a specific infection.
- Recommend pneumococcal vaccine and annual influenza vaccine. In New Zealand, the subsidy for the pneumococcus and influenza vaccine is available for immunosuppressed patients under some circumstances.
- Recommend varicella and influenza vaccines to household contacts (‘ring-fencing’).
Step 4: Vaccinations after starting immunosuppression
- Continue routine non-live vaccination schedule.
- Have seasonal influenza vaccine each autumn and consider a booster in winter if immunosuppression is severe.
- Avoid live vaccinations (MMR and BCG are permitted) of the patient and household members once immunosuppression has commenced.
Immunisation and biological therapies: special situations
- Infants born to mothers who received biologics during pregnancy, particularly in the third trimester, should not receive live vaccines in the first six months after birth. Rotavirus and BCG in particular should be avoided. Non-live vaccines can be given according to the usual schedule. However, it is possible the immune response may be suboptimal.
- Rituximab acts on B-cells which are the antibody-producing cells. The antibody response to an immunisation is therefore impaired for at least 5 months and perhaps up to 12 months after an infusion. If indicated, non-live vaccines should be given at least one month before and at least five months following a rituximab infusion.
Immunosuppressed patients exposed to varicella and measles
Passive antibody protection is required for significantly immunosuppressed patients following exposure to varicella or measles, whether or not they have detectable antiviral IgG antibodies.
Varicella is infectious from two days before the rash appears until the blisters have crusted over. The incubation period is 7–21 days following exposure. ‘Significant exposure’ is defined as 15 minutes or more of close contact/play with an individual with chickenpox or shingles.
Passive protection for an immunosuppressed patient should be provided with varicella-zoster immune globulin (VZIG) within 96 hours (ideally 72 hours) of contact. This is not considered necessary for those on low dose immunosuppression with detectable specific IgG antibodies.
Measles is highly contagious and is infectious from 5 days before the rash appears until 4 days after the onset of the rash. The incubation period is 10–14 days after exposure. ‘Significant contact’ is defined as 15 minutes or more of close contact/play with an infectious individual who has measles confirmed on serology.
Passive protection is required for an immunosuppressed patient regardless of antibody status, using normal immune globulin (NIG) within 6 days (ideally within 72 hours) of contact. MMR vaccination should be given within 72 hours of significant measles contact for non-immunosuppressed individuals.