TGA Laboratories testing report: Measles vaccines monitoring

On this page: Introduction | Testing | Outcomes

Introduction

Measles is an acute, highly contagious viral disease which affects susceptible individuals of all ages. In 2017, the most recent year for which estimates are available, it caused close to 110,000 deaths globally.^[1]

Currently, there is a worldwide measles outbreak. Based on surveillance data, the World Health Organization (WHO) states that globally measles cases have increased almost 300% in the first three months of 2019 compared with 2018.^[1] As of 5 November 2019, there have been 413,308 confirmed cases reported to the WHO.^[2] The WHO states that any community with less than 95% population immunity is at risk for an outbreak.^[2]

Measles was declared eliminated from Australia in March 2014.^[4] However, in Australia, measles cases for 2019 (261 cases) are more than double the 2018 annual total of measles cases (103 cases).^[3] This increase in cases is due to the importation of measles via international travel from countries experiencing outbreaks. Travelers can unknowingly bring the disease from overseas to Australia, where smaller outbreaks and localised transmission may occur.^[4]

The disease is almost entirely preventable through two doses of a safe and effective vaccine.^[1] A highly effective live-attenuated vaccine against measles has been available since 1968 and has been available in Australian immunisation programs since the 1970s. The vaccine against measles is currently provided as a combined vaccine against measles, mumps and rubella (MMR) and is given to children at 12 months of age, and again as the combined measles, mumps, rubella and varicella (MMRV) vaccine at 18 months of age under the National Immunisation Program.

The vaccines work by injecting a child with a small dose of live but weakened (attenuated), measles, mumps, rubella (and in the case of MMRV, varicella) viruses. The weakened virus first multiplies at or near the site of injection and is then recognised by the child's immune system. The immune system responds by making antibodies against the viruses in the vaccine, just as occurs with 'natural' infection, but as the virus is weakened, it does not cause a broader infection and doesn't produce the symptoms and complications of the disease.^[5]

The MMR vaccines are

• M-M-R II powder for injection vial with pre-filled diluent syringe, single dose [AUST R 201877] and
• PRIORIX ALBUMIN FREE VACCINE 0.5 mL powder for injection vial and diluent syringe [AUST R 97842]

and MMRV vaccines are

• PRIORIX-TETRA vaccine 0.5 mL powder for injection vial with diluent syringe [AUST R 107286] and
• PROQUAD measles mumps rubella varicella live virus vaccine injection vial with prefilled diluent syringe [AUST R 126157].

Monovalent measles vaccine is not available in Australia.

To monitor the quality compliance and batch-to-batch consistency of MMR and MMRV vaccines being supplied in Australia, the TGA Laboratories is undertaking a testing project in 2019-20. This project was initiated as part of routine surveillance testing of the quality of the vaccine and not in response to any specific safety concerns.

Testing

A total of 11 samples of MMR and MMRV vaccines (two M-M-R II, four Priorix, one Priorix-tetra and four ProQuad) were tested in a live virus potency test. The results were assessed against the approved specifications for the product and the internationally recognised standard of the European Pharmacopoeia (Measles, Mumps and Rubella vaccine, live #1057 and Measles, mumps, rubella and varicella vaccine, live # 2442).

* Samples were exposed to a higher temperature (37°C for 7 days) and tested in parallel with the samples from the same vaccine batch that had been kept at the recommended storage conditions of 2-8C, in order to check the thermostability of the product.

Outcomes

All samples were found to be of acceptable quality, complying with the approved specifications and the European Pharmacopoeia monograph for measles-containing combined vaccines. The samples tested represent just over 738,000 doses supplied in Australia. The testing also indicates that the manufacturing control strategy that is in place is working to deliver a consistent product of the expected level of quality.

In addition to the laboratory testing, since the start of 2019 the TGA has assessed the manufacturing records of 55 shipments with over one million doses of MMR and MMRV vaccines as part of the ongoing vaccine batch release program which assesses the quality of all vaccine batches before they are supplied in Australia. More information on how we assess vaccines is available at: Vaccines overview.