Side Effects of Shingles Vaccines
Both shingles vaccines cause primarily local injection-site reactions and systemic symptoms, but Shingrix (recombinant zoster vaccine) causes significantly more frequent and intense reactions than Zostavax (live zoster vaccine), though serious adverse events are rare with both vaccines.
Common Side Effects
Shingrix (Recombinant Zoster Vaccine - RZV)
Local reactions (occurring within 7 days) are extremely common 1:
- Pain at injection site: 75-88% (Grade 3 severe pain: 5-11%)
- Redness: 20-35% (>100mm: 1-3%)
- Swelling: 10-21% (>100mm: 0-2%)
Systemic reactions are also very common 1:
- Fatigue: 37-64% (Grade 3: 3-10%)
- Myalgia: 37-58% (Grade 3: 2-8%)
- Headache: 15-44% (Grade 3: 0.1-5%)
- Shivering: 11-31% (Grade 3: 0.4-6%)
- Fever ≥99.5°F: 6-28% (Grade 3 >103.1°F: 0-1%)
- Gastrointestinal symptoms: 13-21% (Grade 3: 1-2%)
The second dose typically causes more intense reactions than the first dose, particularly for systemic symptoms 1. These reactions typically last 1-3 days and are self-limited 1.
Zostavax (Live Zoster Vaccine - ZVL)
ZVL causes substantially milder and less frequent reactions 2, 3:
- Injection-site reactions occur but are predominantly Grade 1 (mild) or Grade 2 (moderate)
- Grade 3 (severe) injection-site reactions are infrequent 3
- Systemic reactions are significantly less common than with Shingrix 2
Serious Adverse Events
Both Vaccines
Serious adverse events (SAEs) occur at similar rates to placebo 2, 4, 5:
- No significant increase in deaths, hospitalizations, or life-threatening events in clinical trials 2
- In immunocompromised populations, SAEs occurred in 7% of Shingrix recipients vs 8% of placebo recipients 1
Rare but Notable Events
Guillain-Barré Syndrome (GBS): A potential rare association with Shingrix has been identified, though data remain limited due to the rarity of confirmed cases 4. Post-licensure surveillance did not detect a sustained increased risk, but uncertainty remains 4.
Disseminated herpes zoster: Can occur rarely with Zostavax (live vaccine), particularly in immunocompromised individuals, which is why ZVL is contraindicated in this population 2.
Infective pneumonia: Reported in 1.5% of Shingrix recipients vs 0.9% of placebo in immunocompromised populations, though causality is uncertain 1.
Important Clinical Considerations
Tolerability Impact on Vaccination
Concerns about side effects significantly reduce vaccine uptake and completion 6:
- Individuals concerned about tolerability are 1.22 times more likely to refuse any dose and 1.83 times more likely to receive only one dose instead of completing the two-dose series 6
- This represents a major barrier to achieving adequate shingles prevention coverage
Immunocompromised Populations
In immunocompromised patients (transplant recipients, cancer patients, HIV-infected individuals), the side effect profile remains similar to immunocompetent adults 1. Importantly:
- No increased risk of graft rejection in renal transplant recipients (3% vs 5% in placebo) 1
- No increased risk of disease relapse or progression in cancer patients 1
- Shingrix is safe in these populations, unlike the live vaccine
Potential Immune-Mediated Diseases
New onset or exacerbation of potential immune-mediated diseases (pIMDs) occurred in 1.3% of Shingrix recipients vs 1.0% of placebo, with no notable imbalances in specific conditions 1.
Rare Long-Term Symptoms
One case report describes prolonged neurological and musculoskeletal symptoms lasting over a year following Shingrix vaccination 7, though such cases appear extremely rare and causality is difficult to establish.
Clinical Pitfalls to Avoid
Failing to counsel patients about expected reactogenicity: The high frequency of local and systemic reactions with Shingrix (particularly after dose 2) should be discussed proactively to prevent vaccine hesitancy and ensure series completion 6.
Confusing reactogenicity with safety concerns: While Shingrix causes more frequent and intense reactions than Zostavax, serious adverse events occur at similar rates to placebo 2, 4.
Assuming live vaccine is safer: While ZVL has milder reactions, it carries the theoretical risk of disseminated disease in immunocompromised patients and has lower efficacy 2.
Not monitoring immunocompromised patients appropriately: Though Shingrix is safe in immunocompromised populations, individual disease-specific monitoring (e.g., graft function, disease relapse) should continue per standard protocols 1.