What are the ingredients of COVID-19 vaccines?

Vaccine ingredients depend on the type of vaccine. As vaccines are approved for use, the contents and presentation of each vaccine is published by Medsafe as a data sheet and consumer medicine information.

These form part of the information that companies submit during the approval process. Find the ingredients for the Comirnaty (Pfizer/BioNtech) vaccine here.

Some other types of vaccines use human cell lines in the vaccine manufacturing process. This is known to be a safe and efficient way to produce vaccines. Both the Janssen and Oxford/AstraZeneca COVID-19 vaccine candidates use cell lines. NO cells from the manufacturing process remain in the vaccine because purification removes all the cell culture material and each batch undergoes thorough quality control checks. The Catholic Church has issued a formal statement saying it is morally acceptable to take vaccines that use cell lines. Find further information on fetal cells and COVID19 vaccines here.

What types of COVID-19 vaccines have been developed?

Multiple types of vaccines are being developed around the world.

We are familiar with some of the vaccine types, such as the protein subunit candidates, like those used in Hepatitis B and whooping cough vaccines; however, other vaccines are using newer technologies such as mRNA and viral vector vaccines. For further information on the types of vaccines that are being developed, please click here.

Can mRNA COVID-19 vaccine affect fertility or affect future babies?

There is no biologically plausible reason why this vaccine could have any effect on our genes or fertility and there is strong evidence it does not.

Vaccination is recommended before and during pregnancy

Women who are trying to become pregnant need not to delay the vaccination nor avoid becoming pregnant. COVID-19 is a potentially very serious disease. Pregnant women and their unborn babies are greater risk of needing hospital care than women who are not pregnant

For more information: see here for advice from the Ministry of Health and here for the advice of the Royal Australian and New Zealand College of Obstetricians and Gynecologists.

Comirnaty and fertility

Shortly after the Pfizer mRNA vaccine, Comirnaty, became available overseas misinformation circulated on social media about negative effects on fertility of vaccinated women. Such statements are misleading and calculated to cause unnecessary fear. There is no plausible reason why this vaccine (or any previously) could have such effects and there is strong evidence that is does not.

Preclinical studies

Every new vaccine or new medicine is tested thoroughly before it can be given to humans, to check for any potential harms prior to conception, during pregnancy or to the baby. If a vaccine candidate fails this stage of testing, further research will be stopped. 

Animal studies have shown no effects on fertility – for this vaccine or other the COVID-19 vaccines approved in New Zealand. For example, when female rats were given very large doses of the Pfizer COVID-19 vaccine (300 times the human dose) before mating and during pregnancy, no changes were seen in mating performance, fertility or any ovarian or uterine measurement. In addition, no effects were seen before or after birth on the survival, growth, physical development or neurofunctional development of the babies.

The vaccine is short-lived

Comirnaty vaccine contains messenger ribonucleic acid (mRNA) inside a fatty bubble which is delivered to muscle cells in the arm when you are vaccinated. The mRNA and its protective bubble are very fragile, so that it needs to be stored at very cold temperatures to stop it from degrading.

Once outside of its lipid bubble, mRNA is quickly destroyed by enzymes (ribonucleases) found everywhere, including inside and outside of our cells. It only has a day or two to do its work. The components of the lipid bubble are also cleared from our body as a waste product. The vaccine gives the body the recipe to make replicas of the COVID-19 virus spike protein and is completely gone within a couple of days.

The quantity of this protein produced after vaccination is much lower than the amount seen in people with COVID-19 infection with the virus spreading throughout their body. Furthermore, as soon as it is produced, this protein is dismantled inside specialist cells and the pieces are shown to the immune system in the lymph nodes nearest to the arm muscle.

The ovaries and testes are protected.

The ovaries or testicles are protected, from infection and damage, by special cells (such as Sertoli cells in males and columnar epithelial cells in females) which prevent cells of the immune system or antigens (such as parts of any vaccine) from entering.

Evidence from fertility clinics

In Israel, patients attending fertility clinics have been carefully studied after having the Comirnaty vaccine. No difference in the in vitro fertilisation (IVF) cycle outcomes, including the number of eggs collected; the number of matured eggs; the fertilization rate; and the number and quality of embryos at day 3, were seen in women who had intracytoplasmic sperm injections (ICSI) before and after two doses of Comirnaty (time from first dose 57± 24 days). Additionally, the number and percentage of clinical pregnancies did not differ significantly between the pre and post vaccination groups. Another study, which looked at women having eggs collected shortly after vaccination (mean 12 days among those having had one dose and 49 days after first dose among those having had two doses), found no differences in follicular function, including hormone production, and oocyte (egg) quality biomarkers. In addition, sperm parameters including semen volume, sperm concentration, sperm motility, and total motile sperm count have been the same in men following vaccination (33 days after first dose). Studies in America have also found no differences in embryo implantation or early pregnancy development nor sperm parameters.

Vaccinated women can fall pregnant

As well as this detailed information about the lack of impact on factors related to fertility, the real-world experience with the vaccine is also reassuring. Numerous women have conceived following Comirnaty vaccination. Looking at participants in the v-safe pregnancy registry in the US, found no difference from the expected spontaneous abortion rate in women who received an mRNA vaccine from 30 days before the first day of their last menstrual period through to 14 days after (NIH preprint).

False alarms

Any alleged similarity between the SARS-CoV-2 spike protein and the human protein, syncytin-1, has been completely disproven. Any amino acid sequences in common are much too short to activate an immune response. Furthermore, antibodies in the serum of women previously infected with COVID-19 cannot recognise or bind to syncytin-1.

Some women have reported their menstrual periods may be early or heavy following the vaccination. This is possible since there is a connection between the immune system and the bleeding of menstrual cycles, but such changes can also occur coincidentally or due to anxiety that some people experience when being vaccinated. Any potential effect is brief and will not affect long term fertility. There is no effect on the placenta during pregnancy because different biological processes maintain the uterus lining.


References

Published articles

  • Bentov Y, Beharier O, Moav-Zafrir A, et al. Ovarian follicular function is not altered by SARS-CoV-2 infection or BNT162b2 mRNA COVID-19 vaccination. Hum Reprod. 2021;36(9):2506-13. doi: 10.1093/humrep/deab182
  • Bowman CJ, Bouressam M, Campion SN, et al. Lack of effects on female fertility and prenatal and postnatal offspring development in rats with BNT162b2, a mRNA-based COVID-19 vaccine. Reproductive Toxicology. 2021;103:28-35. doi: https://doi.org/10.1016/j.reprotox.2021.05.007
  • Gonzalez DC, Nassau DE, Khodamoradi K, et al. Sperm parameters before and after COVID-19 mRNA vaccination. JAMA. 2021;326(3):273-4. doi: 10.1001/jama.2021.9976
  • Morris RS. SARS-CoV-2 spike protein seropositivity from vaccination or infection does not cause sterility. F&S Reports. doi: 10.1016/j.xfre.2021.05.010

Preprint papers, not peer-reviewed

  • Head Zauche, Bailey W, Smoots AN, et al. Receipt of mRNA COVID-19 vaccines preconception and during pregnancy and risk of self-reported spontaneous abortions, CDC v-safe COVID-19 Vaccine Pregnancy Registry 2020-21. Research Square. 2021 (preprint).[accessed 13 Sep 2021; posted 9 Aug 2021] doi: 10.21203/rs.3.rs-798175/v1
  • Safrai M, Rottenstreich A, Herzberg S et al.  Stopping the misinformation: BNT162b2 COVID-19 vaccine has no negative effect on women’s fertility medRxiv preprint  [accessed 13 Sep 2021; posted 01 June 2021] doi: 10.1101/2021.05.30.21258079
  • Safrai M, Reubinoff B  and Ben-Meir A. BNT162b2 mRNA Covid-19 vaccine does not impair sperm parameters medRxiv preprint [accessed 13 Sep 2021; posted 03 May 2021] doi: 10.1101/2021.04.30.21255690
     

Will the vaccine make a person test positive on COVID-19 tests?

No. The vaccine makes a person produce antibodies against the virus spike protein but the nasal swab looks for particles of virus.

The spike protein that is made in your body in response vaccine does not travel far and does not reach your nose.

How long will COVID-19 vaccine immunity (i.e. protection from the COVID-19 disease) last?

We would expect COVID-19 vaccines to provide protection for longer than 2 months, although exactly how long for, remains unknown at this stage. This is because not enough time has passed since the clinical trials started to be able to accurately answer this.

We know that the Pfizer/BioNTech COVID-19 vaccine lasts for AT LEAST two months, because data supporting this has been reviewed by Medsafe. As part of the conditional approval of the Pfizer/BioNTech COVID-19 vaccine, more data is to be provided as it becomes available. It is anticipated that further data will be provided on durability of the immune response post vaccination in coming months.

Will booster doses of a COVID-19 vaccine be needed?

Not enough time has passed since first vaccinations were given to be able to answer this question.

People enrolled in clinical trials are being followed up closely, which will allow this question to be answered in due course. For more information, please click here.

It is expected that small adjustments may be made to the vaccine if the COVID-19 virus changes so much that vaccine loses effectiveness. In this case booster doses will be required to better match the virus variants in circulation, like for the influenza vaccine. How frequently these changes will need to be made is unknown. A major advantage of mRNA vaccine technology is that these changes can be made very quickly (new batches available within a few months compared with more than 6 months for seasonal flu vaccines).

What is the acceptable timeframe between the first and second doses of the Comirnaty vaccine?

To be fully immunised with Comirnaty requires two doses given at least 21 days apart and preferably 6 weeks apart.

Vaccinators are advised not to give the second dose earlier than this, and while longer spacing is acceptable, the recommended spacing is for the second dose to be given at 6 weeks after the first dose.

People at highest risk of exposure to others with COVID-19 are advised to have their second dose at least 21 days after the first to provide more immediate protection. Everyone else can allow 6 weeks between doses to provide a strong immune response and good protection after the second dose. See here for more information.

A closer spacing (at least 21 days) may also be advised for people who are due to commence planned immunosuppressive treatments for longer than 28 days, to provide a good immune response before treatment starts. Do not delay treatment or vaccination. Those who are already receiving such treatments are advised to allow 6 weeks between doses to give the best immune response.

If more than one vaccine becomes available, could taking two different vaccines boost the effectiveness?

We do not know the answer to this yet as it is still being investigated in clinical trials. Currently, the COVID-19 vaccines are not considered interchangeable.

There is limited data available on the interchangeability between COVID‑19 vaccines, such that, where possible other vaccines should not be substituted to complete the course. So far, the only COVID-19 vaccine available for use in New Zealand is Comirnaty (Pfizer/BioNTech). Other vaccines, including the COVID-19 vaccine AstraZeneca and COVID-19 Vaccine Janssen have been approved by Medsafe but their role in the vaccination programmes is under discussion.

To be fully immunised with Comirnaty, two doses are required, to be given at least 21 days apart (ideally, six weeks apart). There is no maximum duration between doses, so it is not necessary to restart the course or give a third dose if it has been longer than 6 weeks since dose one.

For the WHO position on mixing COVID-19 vaccines, please click here.

If you had COVID-19 and recovered, will you still be able to or need to get the vaccine?

Vaccination is being offered to people who have and have not had SARS-CoV-2 infection previously.

Data from clinical trials and from countries with a lot of COVID-19 cases have shown the vaccines to be safe and effective in this group of people. It is expected that the vaccine will boost the immune response and provide good protection for those who have previously had SARS-CoV-2 infection. 

Due to variability in immune response in people who have had a previous SARS-CoV-2 infection (with or without symptoms), an individual is considered fully immunised only after two doses of mRNA-CV (or another COVID-19 vaccine overseas, see FAQ) given at least 42 days apart. It is recommended to start vaccination from 4 weeks after recovery, or from the first confirmed COVID-19 positive PCR test if asymptomatic, and when cleared to leave isolation by a clinician.