World Immunisation Week. Image source: WHO
By Mark Rice, Global Health Campaigns Manager, RESULTS Australia.
As we mark World Immunisation Week this year, the world is making an unprecedented rapid replacement of a vaccine. Between mid April and the beginning of May, 155 countries around the world are withdrawing the current withdraw the current trivalent (three-strain) oral polio vaccine from their routine immunisation systems and replace it with bivalent (two-strain) oral polio vaccine. This is the largest and fastest global vaccine roll-out in history.
The reason for making this rapid switch is that the success of polio vaccination campaigns has led to a change in the risks of using the three-strain oral vaccine. Transmission of the Type 2 polio virus now been eliminated, but in a small number of cases the Type 2 component of the vaccine can lead to a child contracting polio after vaccination. Therefore, moving to the two-strain oral polio vaccine will greatly reduce the risk of children contracting polio as an adverse effect of the vaccine.
The polio vaccine switch illustrates the importance of innovation in vaccines. We need to develop new or improved vaccines for the following reasons:
- The diseases vaccines are intended to prevent evolve, requiring modifications to the vaccines.
- Research and development work on vaccines can lead to lower-cost ways of delivering vaccines (eg, combining several vaccines into one shot) and to minimising the risk of adverse reactions to vaccines.
- For some diseases, we do not currently have an approved vaccine (eg, malaria) or an existing vaccine provides limited protection for a short period (eg, tuberculosis). The combined death toll from these diseases is still 2 million per year.
Of course, the widespread application of the vaccines available already has achieved impressive results. Between 1990 and 2015, the number of children under 5 dying each year has declined from over 12 million to 5.9 million, due in part to increased vaccine use. The following reductions in the number of deaths since 2000, based on the latest data from the World Health Organisation, show the impact of making sure most children are immunised:
- Measles deaths have fallen by 85%
- Pneumonia deaths have declined by 47%
- Diarrhoea-related deaths have fallen by 57%.
Making further gains against these and other diseases requires further action to ensure we have the most effective vaccines available. The challenge is that funding for vaccine development can be a low priority for both governments and private sector producers, for the following reasons:
- The time between conducting initial research on a new or improved vaccine and its introduction is significant, due to the length of time to develop an effective formulation of a vaccine, and the time taken to conduct trials and gain regulatory approval.
- Vaccines are more complex to develop and manufacture than drugs. Pharmaceutical manufacturing is similar to chemistry, with production of a drug in tablet form taking no more than a few weeks. As the Children’s Vaccine Initiative noted in the 1990s, vaccine production has a similar time frame to agriculture: it can take a year or more from the first culture of a vaccine product to its use to protect a child.
- From a medical company’s perspective, the costs and risks with patents, licensing and liability can be greater for vaccines than for other medications.
These factors suggest that support for vaccine development needs to receive increased attention in medical research funding through national medical research institutes and the overseas aid program. For example, Australia provides $10 million per year from the aid program in support for Product Development Partnerships to improve diagnosis and treatment for TB and malaria, but has only invested in a vaccine for malaria through its domestic medical research program. However, the development of new vaccines is essential if our existing support for the development and adoption of testing and treatment for these diseases is going to have a significant impact.
Providing increased support to developing new and improved vaccines will reinforce the impact of the unprecedented pledges by national and private sector donors of $US 7.5 billion to Gavi, The Vaccine Alliance for 2016 to 2020. Increased resources to Gavi allows for many more people to benefit from existing and recently-introduced vaccines, but still leaves some gaps in vaccine coverage for diseases for which effective vaccines are not available.
The slow progress towards the goal of eliminating TB as an epidemic illustrates why improved vaccines are essential. TB claims 1.5 million lives per year, and the number of deaths is declining slowly, due to the more extensive application of the current diagnosis and treatment tools, which are mostly out of date.
The only available vaccine for TB, Bacille Calmette-Guérin (BCG) was invented over 100 years ago! BCG fails to protect against the most common form of the disease, which is TB of the lungs. BCG has had little impact on the global TB epidemic and is not recommended for use in infants with HIV because it can make them sick.
The benefits of new, more effective TB vaccines include:
- Stopping the spread of the disease, including drug-resistant TB.
- Saving the lives of millions of people, including people living with HIV.
- Bringing down the cost of treatment and reducing the financial and economic burden of TB on patients, families, communities, and national economies.
All of these benefits are consistent with the goals that Australia and other donors have for their aid programs, so it is in the interests of governments around the world to increase support for vaccine development.
This blog was also published by ACTION Global Health Advocacy Partnership