The vaccine: weighing it up

Benefits, side effects, and who should not get it

The vaccine at a glance

The recombinant zoster vaccine (Shingrix, RZV) is a non-live, protein-subunit vaccine given as two intramuscular injections, 2–6 months apart. It is approved for adults 50 and over, and for adults 18 and over who are immunocompromised.

How effective is it?

• Immunocompetent adults 50+: Over 90% effective at preventing shingles
• Adults 70+: About 89% effective
• 10-year follow-up: Protection remains at about 73% at 10 years
• Immunocompromised adults: Efficacy varies by condition; lower but still clinically meaningful

Even when shingles does occur after vaccination, episodes are typically shorter and less severe.

Side effects — stated transparently

Side effects are real and common. They reflect the vaccine's strong immune response:

• Grade 3 reactions (preventing normal daily activity) occurred in about 17% of recipients — roughly 1 in 6 people
• These reactions typically last 2–3 days
• Common reactions: injection-site pain (78%), muscle pain (45%), fatigue (45%), headache (38%), fever (21%)
• Most people report that the second dose causes similar or somewhat stronger reactions than the first

The short-term discomfort should be weighed against the alternative: a shingles episode that can cause weeks of pain and, in some cases, months or years of postherpetic neuralgia.

Who should NOT get the vaccine

There are genuine contraindications and cautions:

• Allergy to vaccine components — anyone with a known severe allergic reaction to any component of Shingrix
• Current shingles episode — wait until the acute episode has resolved
• Pregnancy and breastfeeding — no studies in pregnancy; the vaccine is not recommended during pregnancy
• Guillain-Barré syndrome — an observed increased risk of GBS (about 3–6 additional cases per million doses in older adults); the FDA requires a warning in the prescribing information. For those with a history of GBS, the decision should be made with a healthcare provider.
• Moderate or severe acute illness — vaccination should usually be postponed

Weighing it up — honest numbers

For every 1,000 people vaccinated, roughly:

• ~30 shingles cases prevented (over 3 years, compared to unvaccinated)
• ~170 people experience grade-3 reactogenicity that disrupts their normal activities for 2–3 days
• Serious adverse events are rare and occur at similar rates to placebo in clinical trials

The decision is personal. This page provides the numbers. Discuss them with a healthcare professional who knows your medical history.