Wednesday 21 August 2019

Dear Dr Nina: Do I need more immunity after my baby is born?

Ask the GP ...

Photo posed
Photo posed

Nina Byrnes

I am seven months pregnant and am very concerned about the outbreak of measles in Ireland recently. I moved her recently from Australia and am amazed by the amount of people who don't seem to vaccinate their children. I had all my bloods done at the hospital so assume that my MMR is up to date, but what happens after my baby is born?

When will they receive their measles vaccination? Do they need more than one for immunity?

Do I have to keep them indoors until they have full immunity?

A. In recent weeks, seven cases of measles have been reported in north Dublin and Meath. This is very concerning, as measles is a vaccine-preventable illness. Vaccination is offered free to all children. In the USA in 2015 an infection originated in Disneyland California that ultimately caused 170 infections spreading to six states. All the cases here and in the USA occurred in children who had not been vaccinated.

In medicine we talk about herd immunity. This refers to the percentage of people that need to be vaccinated in order to contain the spread of infectious diseases. Measles is highly contagious and a herd immunity of 95pc is considered ideal. In Ireland in 2017 so far we have had a 92pc uptake of the measles vaccine. This is not bad, but we can do better.

There will always be certain people who cannot be vaccinated due to illness, age or other conditions, but unfortunately there are also people who choose not to vaccinate their children. Thankfully we don't see too many cases of vaccine-preventable illness anymore, but the flip side of that is that due to this people forget how serious these illnesses can be.

One in four people infected with measles will require hospitalisation. Those under five and over 20 are most at risk of complications. In 2016, there were 89,780 measles-related deaths globally. The evidence for vaccination is very strong. There has been an 84pc drop in death from measles since 2000 with increasing vaccination uptake. All pregnant mothers in Ireland are checked for immunity to measles. As your immunity hasn't been discussed, do check this at your next appointment.

If you are immune then your immunity does pass to the baby through the placenta. These IgG antibodies will protect your baby during pregnancy and after birth. This is called passive immunity. It is strongest in the first month or so and then starts to wane, but some immunity lasts, usually until about one year. The MMR vaccine is given to babies at one year of age. It is a live vaccine and so it is felt that our bodies respond best to these after about 12 months old. The second MMR vaccine is given in junior infants in school at around age four. About 85pc of children are immune after one vaccine dose and it is felt that about 99pc of people are immune after two doses. MMR vaccine is sometimes recommended earlier if the risk of exposure is high. It can be given from six months of age but as this immunity can wane the child still needs two further doses at one and four years old. An early vaccination is recommended for those travelling to areas where measles has been reported.

To date the HSE has not recommended giving earlier doses related to the recent outbreak and unless you have been directly or inadvertently exposed to one of the cases, no new procedures are in place. Measles is a notifiable disease and pubic health doctors actively track those infected and their contacts.

Thankfully it sounds like you are immune and hopefully by the time your baby is born these cases will be contained and you will be able to progress through the normal vaccination programme. In an ideal world we would achieve full herd immunity and thus declare our country measles-free.

Q. What are adenoids for and what happens if they are removed? Our paediatrician has  recommended that our son have his removed and I am worried it will impact his health

A. Adenoids, like tonsils, help our bodies fight infection. They are located behind the nose, high at the top of the throat behind the nose. Unlike tonsils, they are not visible on looking in the mouth. They are very active early in life and can become quite enlarged. They usually start to shrink from about five years of age, almost disappearing by the teen years.

Enlarged adenoids can cause a nasal tone to the voice. Other symptoms of enlarged adenoids may be mouth breathing, leading to a dry mouth and cracked lips, along with snoring, noisy breathing or restless sleep. Those with large adenoids may also get recurrent ear infections or glue ear.

Large adenoids causing glue ear may lead to reduced hearing, which can have a knock-on effect on speech development. A hearing test can assess this. X-ray of the nasal area and neck may show enlarged adenoids.

In milder adenoid conditions, the GP may prescribe antibiotics and nasal drops to help clear any infection and allow the adenoids to shrink. If symptoms are recurrent or not settling, or if there is associated sleep apnoea (pausing of breathing in sleep), an ear, nose and throat specialist may recommend removal of them. The adenoids are removed through the mouth and no scarring results. General anaesthetic is required but thankfully complications are rare. An overnight stay in hospital is not normally required and children can return to normal activity almost straight away.

Removing adenoids has no negative impact on long-term health. Your son’s immune system will still be strong and able to fight off infection. His health may in fact improve, as if his adenoids were the cause of recurrent infections of the ear, nose or throat, then it is likely that these will no longer occur.

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