Drops, injectibles, or both? And other routine queries on polio vaccine answered

February 12, 2020

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A child is being given polio drops in Bannu. — AFP/File
A child is being given polio drops in Bannu. — AFP/File

Public health expert and an epidemiologist specialising in disease control and eradication, Dr Rana Muhammad Safdar, was recently reappointed National Coordinator for Polio Eradication. His work in reducing polio cases from 306 in 2014 to just eight in 2018 has been widely commended. Recently, he took some time out to respond to the routine queries that parents have regarding the polio vaccine.

Q: Why are there two different types of polio vaccines? Does my child need both?

RMS: The two different types of polio vaccines namely OPV (Oral Polio Vaccine) and IPV (Inactivated Polio Vaccine) are given orally and through an intramuscular injection respectively.

OPV is good for inducing gut immunity (intestinal/surface) as well as humoural (blood) immunity. IPV is better than OPV in terms of quick boosting of humoural immunity which safeguards the individual child against paralysis. However, it doesn’t help in strengthening intestinal immunity like OPV does. As OPV blocks the receptors in the intestines and wild polio virus (WPV) that paralyses the child cannot harbour there to increase in number, it not only helps in promoting immunity of the individual child (both humoural and intestinal) but also helps prevent other children from being attacked by WPV.

Q: Is IPV safe? Does IPV have any side effects?

RMS: Overall, polio vaccine is quite safe in both forms. The only issue with IPV can be the slight pain from the injection or any side effect due to wrongly administering the injection, that is, if it's not given by a trained person and/or in hygienic conditions.

Q: I have given several doses of OPV to my child, so does he/she still needs it every time a polio worker comes knocking?

RMS: The number of campaigns in an area are decided based on the current risk by the technical team of experts. And that current risk depends on several factors. Since giving OPV not only saves the child but also helps in protecting others and in eradicating the crippling disease, it is imperative to give your child OPV drops every time the teams come to your home.

Q: I only want my child to receive one polio vaccine, IPV or OPV, but not both. Is there any evidence that multiple injections of vaccines may increase the risk for adverse events?

RMS: Polio vaccine is the safest vaccine on earth. There are no side effects. IPV is given to have an early boost of the personal immunity and we give only one dose of IPV normally in routine. However, OPV should be repeatedly given to further strengthen the immunity, as well as provide the extra level of gut/intestinal immunity. Only one dose of IPV cannot completely safeguard the child from paralysis and/or harbouring the virus in the intestine which multiplies several folds to reach millions (in number) and affect the same child and/or other children. Hence, administration of at least one dose of IPV and then repeated doses of OPV is suggested and advised.

Q: Aren’t multiple injections painful for the child?

RMS: As the needle is a pointed object, it definitely causes some pain. However, for the use of anything, its indications and side effects are weighed. So, the indications and benefits of vaccines are too many and hence shouldn’t be avoided just because of the slight pain caused by the injection process. Leaving children exposed to different pathogens (disease causing agents) just because of a small duration of pain is not a wise idea at all.

Q: If my child receives multiple injections in the same visit, will the vaccines be as effective if given alone? Can multiple vaccines given at once overwhelm a child’s immune system?

RMS: Vaccines given at the same time are as effective as when given alone. Studies show the same, and for reasons, different antigens (vaccines) are given at the same time. It also saves the time of the parents by decreasing the number of visits as well as decreases the pain of the children because of multiple injections. For instance, five different vaccines are given in just one injection known as Pentavalent (for Diphtheria, Pertussis, Tetanus, Hepatitis B, H. Influenza).

So don’t worry about any side effects (except fever and pain with some injectable vaccines) and opt for the vaccinations as advised by experts for the children's overall health.