Which Covid vaccines are safe in pregnant women?

The recommendation for any woman who is contemplating pregnancy or currently pregnant is to vaccinate. 

In pregnancy the recommended vaccine is the Pfizer or Moderna Vaccine. This is the mRNA vaccine and therefore contains no viral material. Most importantly the mRNA does not transfer across to baby. mRNA gets destroyed in the mother after it produces the spike protein. Indeed within a few weeks the spike protein is destroyed in the mother and the only thing that remains is the antibodies against the spike protein. These antibodies provide protection to baby. 

Astrazenca is safe prior to pregnancy. Should you become pregnant soon after your AZ shot then the second dose of the vaccine would be with either the Pfizer or Moderna vaccine. 

The Covid Vaccine and its safety

We now have very robust data demonstrating the fact that vaccines are safe. 

Its important to understand how drug adverse events are reported. Every single event that happens after a medicine or vaccine is given is reported. The fact that an event occurs after a medication is given does not mean it is caused by a medicine. In the same way any event that occurs after vaccination isn’t necessarily caused by the vaccine. 

The way to determine whether an adverse event is attributable to a drug or vaccine is to determine what the background, or underlying risk of that event occurring regardless of whether the medication or vaccine was given in the first place. 

With the covid vaccine the easiest way of determining whether the vaccine has even effect on pregnancy is to determine whether there has been an increase of an adverse event compared  to pre-covid times (ie 2019) or to unvaccinated people during the same time period. 

When looking at the data, miscarriage will always be reported as an adverse event following a vaccine. However this does not mean the vaccine caused the miscarriage. The largest study shows that the miscarriage rate occurring following vaccination is approximately 15%. We know prior to covid and certainly prior to vaccination, the miscarriage rate for all pregnancies was approximately 25%. Or 1 in 4 pregnancies unfortunately result in a miscarriage. Given that there has been no rise in miscarriage rates (ie 15% vs 25%) we conclude that the vaccine DOES NOT result in an increase in miscarriage. 

Over 5 billion people around the world have been vaccinated. We have data on over 200,000 women in all stages of pregnancy who have been vaccinated. In of itself this represents greater amount of data than we would normally gather from large studies. The vaccine has had more eyes on it than any other drug or vaccine in the history of modern medicine. 

An understanding of how the mRNA vaccine works provides comfort in understanding that it is safe in pregnancy and to babies.  

The mRNA vaccine is taken up by muscle cells and then heads to protein producing factories within the muscle cell to produce the spike protein. Once the mRNA produces the protein it is destroyed (ie no mRNA is left within the body and the mRNA does not change your DNA). The spike protein then sits on the outside of the muscle and the immune system senses it and produces antibodies against it. They in turn destroy the spike protein and our immune system then remembers what to look out for in the future. These antibodies are ready to be deployed if a person comes in contact with the Covid Virus. The antibodies (like all antibodies against all viruses or bacteria) cross the placenta and are also in breast milk; providing protection to the baby.

What are the complications of Covid infection in pregnancy – What happens if you are infected with Covid in pregnancy??

The saying is prevention is better than cure. The reason for vaccination is to reduce illness in pregnant women. 

From July 12^th 2021 until the September 28^th 2021 there was a total of 15,238 cases of Covid-19 in Victoria,

Of the 15,238 cases:

79% were eligible for vaccination at the time of infection 

88% were unvaccinated 

86% of hospitalised Covid-19 cases were unvaccinated

98% of Covid cases admitted to ICU were unvaccinated

The simple message is, Covid vaccines are effective at preventing infection, but also at preventing serious illness and ICU admissions 

As we head out of lockdown there will be an increase in the number of cases of Covid infection. Hence the chance of a pregnant women becoming exposed to infection will be high. With that in mind preventing infection in the first place is the best medicine. 

Pregnant women are not at any increased chance of becoming infected however are more susceptible to the severity of the illness. This is partly due to the changes that occur in the cardiovascular and respiratory systems that occur during pregnancy. Any woman who has been pregnant will tell you that they become puffed with less exertion than they previously had prior to pregnancy.  

Following infection around 90% of women will recover without any hospitalisation. However, 10% of pregnant women will require hospitalisation. The chance of hospitalisation is 5 times greater than non pregnant women.

If admitted there is a 1 in 7 chance a woman will end up in intensive care unit with a 1 in 3 chance of requiring a ventilator to support lung function. Given the complexity of the illness this often results in a woman requiring an emergency birth via a caesarean section 

Unfortunately becoming infected with covid results in the need to birth babies early. Approximately 20-30 % of babies will be born prematurity and with the need to spend time in the Special Care Nursery or Neonatal Intensive Care Unit.

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