In February 2009, the Governing Council of the United Nations Environment Programme (UNEP) agreed on the need to develop a global legally binding instrument on mercury. The overall goal of the instrument is to protect human health and the environment by reducing mercury releases. An issue to be discussed at the next round of negotiations, due to take place in Nairobi from 31 October - 4 November, is the inclusion of thiomersal, a widely-used vaccine preservative used in inactivated vaccines supplied in multi-dose vials, in a list of banned products. If this proposal is adopted, it will have serious negative consequences on the ability of national immunization programmes to vaccinate their populations against a number of vaccine-preventable diseases.
As delegates from governments gather together with representatives from international civil society organisations in Nairobi, Médecins Sans Frontières (MSF) calls on Ministries of Health (MoH) to engage with their committee representatives, in order for the concerns of the health sector to be factored into country positions. MSF also urges the negotiating parties to remove thiomersal from the list of products to be banned.
Médecins Sans Frontières (MSF) uses vaccines that meet the quality, safety and efficacy standards of the World Health Organization (WHO). MSF, like many ministries of health, uses multi-dose vaccine vials containing thiomersal because they are more practical and more affordable than single-dose vials. Most vaccines need to be refrigerated at temperatures between 2-8°C, and multi-dose vials take up less space per dose in the cold chain during storage and transport. Using multi-dose vials also results in fewer vials to dispose of following vaccination campaigns. On a per-dose basis, vaccines in multi-dose vials are also significantly less expensive to purchase from manufacturers.
If thiomersal is banned, however, many immunisation programmes may not be able to reach the same number of children. Manufacturers would have to stop producing multi-dose vials of important vaccines such as pentavalent, which protects children against five diseases—diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type B. The affordable new meningitis A conjugate vaccine, which has halted meningococcal epidemics during pilot introductions in three African countries, and is scheduled to roll out across the continent in the coming years, would be barred from sale.
Switching to single-dose products on a global level would require manufacturers to increase production capacity of such products; the cost of this expansion would cause single-dose vaccine prices to rise. In addition to paying higher prices for affected vaccines, countries would have to expand their cold chain capacity to handle increased product volumes—a process some developing countries already struggling to maintain adequate immunisation coverage might not be able to afford. These additional costs and logistical challenges incurred by a thiomersal ban would further impede immunisation programmes’ ability to deliver vaccines to children and protect them against preventable diseases.
Currently, no alternative WHO-approved vaccine preservatives have been proven effective for products that would be affected by a thiomersal ban. Even if alternative preservatives were tested or developed, and manufacturers re-formulated their vaccines, products with new elements would need to be tested and re-submitted to regulatory authorities for approval. This process would take years, and in the meantime, vaccination programmes would suffer.
In a submission to the UNEP negotiations, the WHO reiterated its recommendation for the use of multi-dose vaccines containing thiomersal1. The WHO Global Advisory Committee on Vaccine Safety has monitored the use of thiomersal in vaccines for over a decade, and found no evidence that the amount of thiomersal contained in vaccines poses a health risk2. Similarly, while the United States and many European countries use only a limited number of thiomersal-containing vaccines, their regulatory authorities have not found evidence that thiomersal, which has been used in vaccines since the 1930s, is detrimental to the health of children3, 4.
MSF supports UNEP efforts to eliminate and reduce risks from mercury compounds that are harmful to human health. However, allowing the continued use of thiomersal is critical to ensuring the successful continuation of vaccination programmes. Given the negative consequences a thiomersal ban would have on immunisation programmes and global efforts to vaccinate against deadly diseases, a thiomersal ban should be removed from consideration in UNEP negotiations.