Covid vaccines are proving highly effective in pregnancy, according toa newly published studyin the American Journal of Obstetrics and Gynecology. It has also found that mothers who have been vaccinated are passing on precious immunity to their newborns.
A group of researchers in Massachusetts studied pregnant women’s response to two approved mRNA vaccines – Pfizer/BioNTech and Moderna/NIH. The women were vaccinated either during pregnancy or while breastfeeding, and their ability to produce virus-specific antibodies was compared to that of vaccinated, non-pregnant women.
While the small number of women included in this study – 131 – is a limiting factor, it nonetheless provides very important early insight into the safety and effectiveness of COVID-19 vaccination in pregnancy. This matters, because new infectious diseases can come with all kinds of risks for women during pregnancy and childbirth, as well as in the neonatal phase. All of these risks need to be considered when making healthcare decisions related to pregnant women and, in particular, when considering vaccine strategies.
Known risks
While there remains a lot that we don’t yet know about the effects of COVID-19 on pregnant women and their babies, there are some things we do know.
In early pregnancy, the virus is not associated with an increased chance of miscarriage. Vertical transmission – where the virus passes from the mother to the baby in the womb – is relatively rare. And babies seldom get sick.
We also know that, overall, pregnant women tend to have milder symptoms than the general population. However, they remain at greater risk of complications including placental inflammation and can become very ill. This in turn can lead to an increased likelihood of being admitted to intensive care and giving birth prematurely. As within the general population, pregnant women who are Black or Asian, as well as those who are obese, are at greater risk of severe COVID-19.
Now, of course, vaccination would prevent these outcomes. However, women are typically not included in any early vaccines trials if they’re pregnant. It is only now that data relating specifically to the response to the vaccine of pregnant and breast-feeding women are emerging. The work published in this paper is the first study to address this, making it incredibly valuable.
Antibody response
The Massachussets study focused on 84 pregnant women, 31 who were breast-feeding and 16 who were neither. The women each received two doses – what is known as prime and boost – of one of the vaccines. They had blood taken with each dose, and again up to six weeks after the second.
These blood samples were used to track the women’s antibody responses to the virus. The results were conclusive. All the women – both pregnant and breast-feeding – were found to have robust immunity, comparable to that of the non-pregnant women. And, this immunity increased with time, post-vaccination.
The researchers compared these findings with the antibody response in pregnant women who had contracted the virus naturally. This enabled them to show that the level of antibodies made in response to the vaccines far exceeded those made in response to natural infections.
Passive immunity
One important reason to vaccinate pregnant women is so they can in turn provide their antibodies to the baby. This is known as passive immunity and it occurs when a mother is infected naturally or when she is vaccinated. The antibodies she produces are passed to her baby through the placenta or via breast milk. This affords the baby protection against infectious diseases it might come in contact with while its own immune system is still maturing. It is one of the reasons, for example, that pregnant women in many countries, including the UK, are encouraged to be vaccinated for flu and whooping cough.
When the babies in the study were delivered, the researchers studied blood samples from their umbilical cords. They found virus-specific antibodies in every sample. This shows that vaccinated mothers are passing antibodies to their babies through the placenta, in keeping with what we know from studies in natural infection. They also found virus-specific antibodies in breast milk from the women who were breastfeeding when vaccinated, which means that passive immunity is taking place via this route as well.
The investigators in this study were also able to provide some insight into when in pregnancy might be the best time to vaccinate pregnant women. Vaccinating women in different trimesters of their pregnancies did not affect antibody levels. This suggests that women can make a robust response to the vaccine at any stage of pregnancy.
In contrast, the analysis of umbilical cord blood shows that the second dose of a vaccine is important for maximising passive immunity for the baby. The lowest levels of antibodies in the umbilical cord samples came from a woman who delivered her baby before the second dose. The ability of the antibody to stop the entry of the virus into cells and cause infection also seems to need the boost dose. This suggests that having both doses before giving birth is critical to ensuring the baby gets the most protection possible.
Next steps
There have been recent calls for pregnant women to be included at the early stages of vaccine trials, in order to limit delays in protecting them and their newborns. This study supports those calls.
It also highlights important next steps. Larger studies are needed to investigate when the best time in pregnancy is to vaccinate. These should include more detailed analysis of how the mothers respond to the vaccine at different stages of pregnancy, whether the vaccine prevents placental inflammation and preterm birth, and what effects this timing might have for passive immunity in newborns.
It points to other important questions too. How effective is the immunity transferred to the infant? And how long-lived is vaccine-induced viral immunity in the mother when the vaccination is made during pregnancy? We will need more studies to answer these questions.
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
