There are two types of COVID-19 vaccines available in Hong Kong at the moment – CoronaVac produced by Sinovac Biotech and Comirnaty produced by Fosun Pharma / BioNTech. CoronaVac is an inactivated virus vaccine that uses a dead virus to help our bodies develop an immune response. The dead virus cannot replicate inside our bodies and so it will not cause an infection. Comirnaty is an mRNA vaccine. Unlike traditional vaccines, an mRNA vaccine does not contain actual part of the virus. Instead, the mRNA gives our cells instructions to make the virus’ distinctive spike protein. Our bodies recognize the protein and build immunity that will remember how to fight the virus that causes COVID-19 if we get in contact with the virus in the future. An mRNA vaccine does not contain the live virus, so it cannot cause an infection. In addition, the mRNA contained in the vaccine does not enter the nucleus of the cell where our DNA is kept, and therefore does not interact with a person’s DNA or cause genetic changes.
As of 17th May 2021, more than 110,000 pregnant women in the United States have been vaccinated against COVID-19, where the majority of COVID-19 vaccines are mRNA vaccines including Pfizer-BioNTech and Moderna, the latter is not available in Hong Kong. There has been no safety concern raised so far. Based on data from the United States, the Hong Kong College of Obstetricians and Gynecologists (HKCOG) issued the latest guidelines on 5th May 2021, recommending women who are planning pregnancy, are in the immediate postpartum, or are breastfeeding be vaccinated with mRNA COVID-19 vaccine Comirnaty, depending on their age and clinical risk group; and pregnant women should discuss the risks and benefits of vaccination with their doctor. However, CoronaVac has not published its safety data in pregnant and lactating women in the medical literature so far. Hence, CoronaVac is not recommended for use in pregnancy and during breastfeeding at present.
For detailed information, please refer to the HKCOG website:
Can COVID-19 vaccine affect fertility?
While fertility was not specifically studied in the clinical trials of the vaccines, no loss of fertility has been reported among trial participants or among the millions who have received the vaccines, and no signs of infertility appeared in animal studies. From a scientific point of view, the COVID-19 vaccines should not affect the fertility of men or women.
Should women who are planning to conceive receive a COVID-19 vaccine?
Yes. Women who are planning to conceive are advised to have the vaccine before trying for a pregnancy so that they can be protected from getting the infection during pregnancy. However, the Vaccination Fact Sheet for CoronaVac states that ‘The data collected from clinical trials on women with unexpected pregnancy after vaccination are very limited, and it is insufficient to decide the risk of adverse pregnancy outcomes after vaccination.’
For detailed information, please refer to the COVID-19 Vaccination Programme website published by HKSAR Government:
Therefore, HKCOG recommends women who are planning pregnancy be vaccinated with mRNA COVID-19 vaccine Cominarty.
How soon after having a COVID-19 vaccine can I start trying for a pregnancy or start fertility treatment?
The American College of Obstetricians & Gynecologists (ACOG) in the United States recommends that there is no need to delay trying for a pregnancy after completing both doses of the COVID-19 vaccine. Furthermore, the Royal College of Obstetricians & Gynaecologists (RCOG), the British Fertility Society and the Association of Reproductive and Clinical Scientists in the UK recommend couple that they can start fertility treatment immediately after vaccination. The Hong Kong College of Obstetricians & Gynaecologists (HKCOG) has also stated that there is no need to delay trying for a pregnancy after receiving COVID-19 vaccines.
Should I delay my fertility treatment until after I have had the COVID-19 vaccine?
The only reason to consider delaying fertility treatment until after you have been vaccinated would be if you want to be protected against COVID-19 before you are pregnant. The chance of successful treatment is unlikely to be affected by a short delay of up to 6 months, particularly if you are 37 years of age or younger. However, delays of several months may affect your chance of success once you are over 37 and especially if you are 40 years of age or older. Even if you conceive after having received the first dose of Cominarty vaccine, you can still have the second dose after the recommended 3-week interval. If you are still concerned with the safety of the vaccine for pregnant women, you can choose to skip the second dose. Please note that HKCOG recommends pregnant women to receive mRNA vaccines if they have to be vaccinated. If you conceive after having received the first dose of CoronaVac vaccine, you have to discuss with your doctor to see if you need to start a new vaccination programme using Cominarty.
Can I still have a COVID-19 vaccine if I am pregnant?
Although the overall risk of severe illnesses from COVID-19 infection is low, pregnant women are at an increased risk for having such severe illnesses when compared to non-pregnant population, and the risk is more likely to occur during the third trimester of pregnancy. Furthermore, symptomatic COVID-19 infection also increases the risk of preterm birth by 2–3 fold.
Ever since the introduction of the various types of COVID-19 vaccines since late 2020, as of 17th May 2021, more than 110,000 pregnant women in the United States had received the COVID-19 vaccines. The majority received Pfizer-BioNTech or Moderna vaccines which are mRNA vaccines. There has been no safety concern raised so far. The Centers for Disease Control and Prevention (CDC) in USA is still following up on the pregnancy outcomes of these women.
For detailed information, please refer to CDC website:
In general, the World Health Organization and the CDC consider immunization with inactivated vaccines during pregnancy is not expected to be associated with any increased risk to the fetus. However, previous clinical trials of the COVID-19 vaccine using inactivated viruses did not include pregnant or lactating women. Hence, the safety of inactivated COVID-19 vaccine in pregnant and lactating women has not been established yet.
On 22nd April 2021, the Centre for Health Protection (CHP) of Hong Kong has revised interim recommendations and advised pregnant women to consult their obstetricians about the use mRNA COVID-19 vaccines if they wish to consider vaccination. The HKCOG issued a similar recommendation at the same time, which was revised on 5th May 2021. In the latest version of the HKCOG recommendations, it is clearly stated that pregnant women should choose the mRNA vaccine Cominarty.
For detailed information, please refer to CHP and HKCOG websites:
The Vaccination Fact Sheet for Comirnaty states that ‘Pregnant women who consider BioNTech/Comirnaty vaccines (CONVD-19 mRNA vaccines) should consult their obstetricians on the risks and benefits of vaccination.’ The Vaccination Fact Sheet for CoronaVac states that ‘The clinical data of pregnant and lactating women are not available at present.’
For detailed information, please refer to t heCOVID-19 Vaccination Programme website published by HKSAR Government:
Should women with recurrent miscarriages avoid having a COVID-19 vaccine?
No. There is no reason to avoid having COVID-19 vaccine as it will not affect women’s risk of having a miscarriage.
Disclaimer: HKRHC is not liable for any damages related to the use of the information contained herein. HKRHC cannot guarantee correctness, completeness or accuracy of the information contained in this document. The advice for COVID-19 vaccines for those trying to conceive or those who are pregnant already is rapidly developing and the latest data or best practice may not yet be incorporated into the current version of this document. HKRHC recommends that patients always seek the advice of their doctors if they have any concerns.