Vaccines and common question surrounding vaccination – by Dr L. Ramouthar
World immunisation week started in April with its call to “protect your world, get vaccinated”.
The KwaZulu Natal Department of Health is due to begin catch up immunisation against Polio and Measles. The first phase begins 28th April to 17th May against Measles and Polio. The second phase continues from 18th May to 27th June and is only against Polio. This campaign is aimed toward all children less than 5 years of age.
But should we as medical practitioners, parents and communities in general worry about vaccination?
Vaccination averts an estimated 2 to 3 million deaths every year, protecting children from diphtheria, measles, pertussis (better known as whooping cough), pneumonia, polio, rotavirus diarrhoea, rubella (or German measles) and tetanus.
Unfortunately, there are still an estimated 22 million children in developing countries that are still not protected against these dangerous diseases using the basic vaccines. In recent years both developing and developed countries has seen a huge failure to vaccinate one’s child. It may be due to complacency or misconceptions regarding vaccines, such as the myths that vaccines do not work or myths surrounding the nature and frequency of side effects. This has led to resurgences of diphtheria, measles and rubella in both developing and developed countries alike. In fact outbreaks of measles have occurred in France, Italy, Spain, The United Kingdom and Pakistan.
So here are answers to questions that parents and healthcare providers alike may have with regard to vaccines.
Where have vaccines come from?
The word vaccine is derived from the Latin word “vacca” meaning cow. Vaccination was discovered in 1796 by Edward Jenner. It was known that if a person had smallpox and survived, he or she would not get the disease again. Sometimes people tried to inoculate themselves against smallpox by purposefully contracting a mild case. But Jenner found that if he gave a person serum from a cow (vacca) that had cowpox (a virus similar to smallpox) then that person was protected from smallpox without having to be exposed to the disease itself. This led to the formation of a vaccine against smallpox, which with time and experience was improved in its stability and ability to prevent smallpox. One hundred and fifty years later, it was completely eradicated so that we may never again be affected by the dreaded disease of smallpox!
The last naturally-occurring case of smallpox in the world was contracted in October, 1977 by a young man Somalia. He survived, and no new cases were reported in Somalia or elsewhere. But ironically, in 1978 two more cases popped up in Birmingham, England, from a smallpox virus that escaped from a research lab. One of the patients died. The director of the laboratory committed suicide. These were smallpox’s last victims. In 1979, a global commission certified that smallpox had been eradicated, and this certification was officially accepted by the 33rd World Health Assembly in 1980.
Vaccines have been designed to encourage one’s body to develop a defence against a particular disease so that when one is exposed to that particular disease one can fight it off with ease.
When one comes into contact with an infective organism (if we consider the common flu for example), the organism gets into the body (inhaled from the air after an infected person sneezes or coughs, or through contact across hands), travels to the site where it intends to multiply and thereafter be carried to the next victim (the flu virus infects the respiratory tract including sometimes the lungs, multiplying there and waiting to be transmitted when the person coughs or sneezes in response to the irritation it causes to the airways), only to start the next cycle in the next victim. The organism’s only purpose is to ensure survival by infecting numerous victims. It can only multiply within a living host. The more people it infects the more it can be transmitted into the environment and to other victims.
Once the organism gets into our bodies however, our body’s immune system recognises the organism as not belonging to the body and it launches an attack upon the organism to try and rid the body of it. During this battle numerous chemicals are released which contribute to us feeling so miserable. If the immune system cannot control the invasion the virus eventually takes over our body and we weaken with disease until we eventually succumb to it. If our immune system is healthy it can destroy all the organisms and in so doing cure us of the illness. That is why our immune system is so important and why we speak of healthy living. It is simply to ensure that our natural defences, our immune system, are kept healthy.
Vaccines simply prime our immune systems to recognise an invading organism early enough and launch an attack large enough to quickly rid the body of the disease. This happens because exposure to disease the second and subsequent times around activates an already alert immune system and the resulting response is greater than if exposure occurred for the first time.
Simply put, vaccines are safe parts of an infecting organism that stimulate the immune system to recognise and prepare for the real infecting organism. It is somewhat like a spy, a part of the enemy that is actually on our side that warns us that the enemy is coming so we can prepare our defence in time. When we administer a vaccine, the body recognises it as being foreign and mounts a defence against it which is even greater and quicker when the body is infected with the real offending organism. This ultimately leads to the immune system overwhelming the organism and destroying it completely.
Can vaccines cause disease?
Vaccines intend to stimulate the immune system so they have to resemble the organism in some way. However, they have been extensively researched to be safe. Vaccines are either part of an organism or the whole organism but the structure of which has been modified. In cases of whole organisms, the organism is either killed or live but attenuated.
Vaccines containing live viruses that have been altered or attenuated include Measles, Mumps, Rubella, Varicella and nasal Influenza. Inactivated or killed vaccines include Polio, Hepatitis A and intramuscular Influenza. Hepatitis B and HPV (Human Papilloma Virus) vaccines are recombinant products, whereas Rotavirus is a reassortment. Pertussis, Haemophilus Influenza B and Pneumococcal vaccines are immunogenic components of bacteria and in the case of Diptheria and Tetanus these are toxoids.
Why do we need to vaccinate our children?
The whole idea of vaccinating a child is to prevent the severe form of a disease and possible death. Infective diseases are commonly spread by close contact between people, hence the more children or people vaccinated the less risk of a child coming into contact with the organism. The aim is to eventually resist the spread and survival of the organism ultimately leading to complete eradication as with smallpox.
What if I choose not to vaccinate my child?
Should a child not be vaccinated, that child is at risk of contracting the disease. Furthermore, that child becomes a source of infection to other children putting others at risk of disease and contributing to the propagation of the organisms. If enough children are vaccinated, it may be that the child never comes into contact with the organism, hence explaining why some children can boast lack of disease despite not being vaccinated. However, with time, lack of immunisation increases the number of people at risk. The organism can then easily infect and cause disease and propagate itself rapidly in a susceptible population, leading to an outbreak.
earch also suggests that vaccination may protect against certain childhood cancers. J Pediatr. 2011;158:996-1002
Can I vaccinate my child with egg allergy?
Influenza vaccine contains limited amounts of egg protein. The influenza vaccine should not be given to people with a true egg allergy. These are people who become extremely sick when exposed to egg and hence cannot tolerate even small amounts of egg. In mild egg allergy, an allergist may be able to give the vaccine in small amounts over many hours, while closely monitoring the person for an allergic reaction. If one is not sure of egg allergy, such as in infants the doctor can perform skin testing using the vaccine.
The MMR vaccine is produced in chick fibroblast cell cultures but the vaccine does not contain sufficient egg proteins to which a person with egg allergy would react. Hence the MMR vaccine is safe in a child with egg allergy.
Yellow fever vaccine, a non-routine vaccine given to people travelling to Central/South America, does contain significant amounts of egg proteins and should not be given to people with egg allergy. In the case of uncertainty of egg allergy again skin testing can be performed prior to administration of yellow fever vaccines.
When do vaccines not work?
Vaccines will not work well if the immune system cannot mount a response to the vaccine. This occurs in cases where the immune system is compromised such as when a person is taking immunosuppressive treatment such as cancer medication or a prolonged course of oral steroid medication, in cases of Diabetes, severe malnutrition or AIDS (Acquired Immunodeficiency Syndrome).
Also, the body may already have some circulating defence against a particular organism already as occurs during breastfeeding when the mother transmits her immunoglobulin over to the child through the breast milk. This may not always allow the baby’s immunity to form completely against the vaccine. This does not mean that mothers should not breastfeed as breastfeeding offers protection against many infectious illnesses by way of this passive immunity. Also, this passive immunity wears off by eighteen months of age. That is why repeated doses of certain vaccines such as Measles are needed. These additional doses act as boosters, maintaining immunity against the disease at maximum.
If I bring my child in for vaccination, how should I prepare for it?
You can easily vaccinate your child at a local clinic, but if you wish to be seen by a doctor, inform your doctor that you wish to vaccinate your child. Give your child some pain relief prior to the appointment. Paracetamol works best when given an hour before a painful procedure. Give the right dose according to your doctor’s instructions or the package insert.
What should I expect following vaccination?
Vaccines are drugs and as with any drug there are side effects. The common side effects of vaccination include local area redness or swelling, a low grade fever and mild irritability. This normally responds to simple analgesia.
If your child has a very high fever, or a fever that lasts for more than three to four hours; or the child’s behaviour is concerning consult your doctor for further advice.
What are the dangers of vaccination?
In extremely rare cases a child may show severe allergy to a component in the vaccine. This occurs almost immediately and can be managed effectively by an experienced health care worker. There have been numerous studies around MMR or any of the vaccines causing autism and the consensus is that there are no associations with autism.