Adverse events following immunisation
An adverse event following immunisation (AEFI) is a medical incident that takes place after an immunisation and is believed to be caused by the immunisation. Although modern vaccines are safe, no vaccine is entirely without risk. After immunisation, some people experience reactions ranging from mild local reactions to (rare) life-threatening illnesses. In some cases, these reactions are caused by the vaccine; in others, they are caused by an error in the administration of the vaccine; and in others, there is no causal relationship. Whatever the cause, an AEFI may upset the public and lead to refusal of (further) immunisation. If this is allowed to occur, thousands of people will continue to contract vaccine-preventable diseases and die each year. Therefore, each AEFI requires a thorough investigation to establish whether it is caused by the vaccine itself, by an error in the administration of the vaccine, or its occurrence merely coincided with vaccine administration (i.e. it is not related to the vaccine or its administration). Staff should be trained in diagnosing, treating, investigating and reporting of AEFI, and in differentiating between mild non-significant reactions and more serious events.
Although people often think that a medical incident after an immunisation must be caused by the immunisation, many such incidents are coincidental. Another belief, that vaccine is the most common cause of AEFI, is also mistaken. Programme error, which can be prevented, is more often the cause. Programme error can generally be prevented through proper staff training and an adequate supply and proper use of safe injection equipment and diluents. Diluents supplied with a vaccine are part of the licensed product and are specific for each vaccine. The vaccine package is not complete without the diluent. Diluents are specifically designed for the needs of each vaccine with respect to volume, pH and chemical properties of the final solution containing the immunising agent. Using the wrong diluent may result in incorrect doses of vaccines, local or general reactions or even death. It is essential that diluents for vaccines are stored, distributed and used in the proper way so that they are not the cause of adverse events or incorrect doses. Tragedies have occurred, related to reconstitution of freeze-dried vaccines with insulin, muscle relaxant and other wrong solutions.
In 1999 WHO established the Global Advisory Committee on Vaccine Safety (GACVS) to respond promptly, efficiently, and with scientific rigour to vaccine safety issues of potential global importance. GACVS held its 19th meeting in
A report of this meeting is available from http://www.who.int/wer/2009/wer8405.pdf
More information on adverse events following immunization is available from http://www.who.int/immunization_safety/aefi/en/
Vaccines do not cause autism
A global increase in the prevalence of autism (most probably driven by broadened diagnostic criteria and increased awareness) has fuelled concerns that an environmental exposure like vaccines might cause autism. Three specific hypotheses have been proposed to support theories that vaccines might cause autism: (1) the combination measles-mumps-rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins; (2) thimerosal, an ethylmercury-containing preservative in some vaccines, is toxic to the central nervous system; and (3) the simultaneous administration of multiple vaccines overwhelms the immune system.
In the 15 February 2009 issue of Clinical Infectious Diseases, Drs Jeffrey Gerber and Paul Offit of The Children’s
Injection safety
A safe injection is one that does not harm the recipient, does not expose the provider to any avoidable risk, and does not result in any waste that is dangerous for any other people. A sterile packaged syringe and needle must be used for each injection and they must be disposed of safely immediately after use. Single-use syringes (preferably auto-disable syringes) and needles are appropriate for all types of immunisation strategies, including use in fixed clinics, outreach sites and mass campaigns. Auto-disable (AD) syringes are designed so that it is impossible to use them more than once.
AD syringes virtually eliminate the risk of patient-to-vaccinator transmission of blood-borne pathogens (such as hepatitis B or HIV) because they cannot be re-used. Of course, they do not prevent needle stick of health workers, particularly if recapping still takes place. To prevent risk of infection, the safe disposal of used needles and syringes is a critical component of any vaccination programme. Without recapping, vaccinators should place needles and syringes in safety boxes immediately after administering vaccines. To avoid an accidental needle prick during disposal, safety boxes should not be over-filled. When the safety box is about three-quarters full, it should be securely shut and stored in a safe place until it can be properly disposed of.
More information on injection safety is available from http://www.who.int/immunization_safety/safe_injections/en/
Cold chain
Vaccines must be stored at the proper temperature in order not to degrade before use. A vaccine that has lost its potency before administration is not only useless in terms of protecting against disease it may also cause undesirable events. The system for guaranteeing vaccine quality is generally referred to as the “cold chain”. The cold chain consists of the network of refrigerators, cold stores, freezers and cold boxes organised and maintained so that vaccines are kept at the right temperature to remain potent during vaccine orders and supplies, their transportation, storage and distribution from manufacturing factory to the point of administration to the target population as well as the accompanying human, material and financial resources.
EPI managers at all administrative levels should attach high priority to the maintenance of the cold chain including the main equipment and cold rooms. Storekeepers and repair technicians should receive proper training to manage this important component of the EPI. Only by doing so can the safety of the cold chain be assured. The cold chain is an integral part of any immunisation programme and, as such, it should be seen within the entire EPI management framework (planning, monitoring and evaluation). During the planning of immunisation activities, EPI management should determine the best possible cold chain option as well as ensure the availability of high-quality vaccines at all administrative levels in the country.
More information on the EPI cold chain is available from http://www.who.int/vaccines-documents/DoxGen/H5-CC.htm
Communication
Communication is an essential component of the EPI. Effective communication helps to mobilize resources for the immunisation programme (advocacy); encourages wide participation and ownership among all stakeholders (social mobilisation); and leads to positive changes in knowledge, attitudes and behaviour in the community served (behaviour change). EPI staff should maintain permanent dialogue not only with vaccinators but also with the whole community, including caregivers and political, traditional and religious leaders, to enhance their understanding of the importance of immunisation for the protection and quality of life of children.
Advocacy might be best characterized as any effort to influence policy and decision makers, to fight for social change, to transform public perceptions and attitudes, to modify behaviours, or to mobilise human and financial resources. In order to improve immunisation and child health, advocacy might encompass all these definitions in one form or another. Anyone can be an advocate – the only requirement is to actively support a cause. Advocates for immunisation can include health or child-focused nongovernmental organisations (NGOs), international and regional agencies, government officials, researchers, health providers, private business people, parents, young people, faith groups, and community members.
More information on communication for EPI is available from
http://afro.who.int/ddc/vpd/epi_mang_course/docs/english/mod%2003.rtf