JYNNEOS mpox (monkeypox) vaccination – dose 2 better tolerated than dose 1

New vaccine safety data published by AusVaxSafety show individuals experience fewer side effects, are less likely to visit a doctor or emergency department and have less disruption to routine activities in the days following dose 2 JYNNEOS mpox (monkeypox) vaccination compared with dose 1.

Subcutaneous JYNNEOS mpox vaccine

There was a 12 percentage points drop in the rate of respondents reporting at least one side effect in the first seven days after their subcutaneous dose 2 JYNNEOS mpox vaccine compared with dose 1 (37% versus 49%). Local pain, fatigue and headache were the most commonly reported side effects across both doses.

To date, AusVaxSafety has not received any report of a visit to the doctor or emergency department following dose 2, compared to 0.9% of respondents following dose 1. The impact of symptoms on daily activities was lower following dose 2 (3%) than dose 1 (4%).   

Subcutaneous vaccine administration uses a short needle to inject a 0.5 mL dose of the JYNNEOS mpox vaccine into the fatty tissue layer (subcutaneous layer) located between the skin and the muscle.

Intradermal JYNNEOS mpox vaccine

There was a 9 percentage points drop in the rate of respondents reporting at least one side effect in the first seven days after their intradermal dose 2 JYNNEOS mpox vaccine compared with dose 1 (51% versus 60%). Local pain, fatigue and headache were the most commonly reported side effects across both doses.

Individuals were also less likely to visit a doctor or emergency department in the days after dose 2 (0.7%) compared with dose 1 (0.8%). The impact of symptoms on daily activities was also lower following dose 2 (1%) than dose 1 (4%).   

Intradermal vaccine administration uses a short needle to inject a 0.1 mL dose of the JYNNEOS mpox vaccine into the space between the two outer layers (epidermis and dermis) of the skin.

To collect data, AusVaxSafety distributes a short online survey via SMS or email to individuals who received their JYNNEOS mpox vaccine at a participating AusVaxSafety site, allowing participants to report any adverse events they may have experienced at different time points after their vaccination. 

De-identified data from completed surveys are analysed and monitored by epidemiologists and vaccine experts to ensure that the vaccine is performing as safely as it is expected to in real-world conditions.

AusVaxSafety will continue to monitor JYNNEOS mpox vaccine to ensure continuing safety and safety data are updated on the AusVaxSafety website fortnightly.

Click here to access the latest JYNNEOS mpox vaccine safety data