Pregnant Women and the H1N1 Vaccine

Pregnant women in Montreal are not getting their H1N1 shots. Despite elevated health risks and being in a group that was prioritized for vaccination from the beginning of the campaign, roughly half of expectant mothers have not yet been vaccinated against swine flu. ("Only half of pregnant women vaccinated against H1N1: health authorities")

"Pregnant women are rigorously counseled to avoid any drugs, diagnostic tests, or treatments that might impact the developing embryo or fetus," says Amy Tuteur, author of How Your Baby Is Born. ("Why pregnant women should get the H1N1 flu vaccine") The obstetrician-gynecologist says women may develop a reflexive fear of vaccination during pregnancy, despite the fact that many vaccines can be administered safely to expectant mothers.

Is H1N1 Vaccine Safe?

People who have opted not to be vaccinated against H1N1 influenza often cite safety as their main concern. Because the vaccine was developed so quickly, they say, it is untested and the its safety is uncertain. Actually, H1N1 vaccine was manufactured using the same process as seasonal flu vaccines. Both the adjuvanted and unadjuvanted formulations use existing technologies and components. We have not previously seen adjuvanted influenza vaccine in Canada, but it has been used safely for some time in Europe.

The World Health Organization now has data on 65 million doses of H1N1 vaccine administered in 16 countries. One adverse side effect is reported for every 10,000 doses of vaccines administered, that is 0.0001 percent. Only five of every 100 reports of adverse effects (0.000005 percent of all vaccines administered) concerns serious effects such as fever, allergic reaction or convulsions. ("Severe reactions to H1N1 vaccine in Canada: WHO", "Only a handful of serious side effects from H1N1 vaccine")

Canada's chief public health officer, Dr. David Butler-Jones, says this is about what would be expected with any vaccine. "The benefit of immunization -- the prevention of serious illness and death -- far outweigh any theoretical risks associated with being immunized," he said. ("Only a handful of serious side effects from H1N1 vaccine")

Is H1N1 a Serious Risk for Pregnant Women?

People who opt not to be vaccinated frequently say the risk of H1N1 influenza is exaggerated. It is true that in the early days of the virus health officials were not sure what they were dealing with, and that information for pregnant women in particular has changed with time.

That being said, expectant mothers are at an elevated risk any time they get the flu. Pregnant women were among the first groups targeted to receive H1N1 immunization in Canada because of this risk. Getting influenza during pregnancy can result in a greater number of respiratory issues, including pneumonia and severe respiratory distress that requires hospitalization. There is also an elevated risk of premature delivery or miscarriage. Risk is greater in the second and third trimesters of pregnancy, and for women within the first six weeks after childbirth. ("Information on pregnancy, breastfeeding and H1N1 flu virus")

Dr. Tuteur encourages expectant mothers to get their swine flu shot. "According to the CDC, there have been approximately 700 reported cases of H1N1 in pregnant women since April. Of these, 100 women have required admission to an intensive care unit and 28 have died. In other words, 1 out of every 25 pregnant women who contracted H1N1 died of it," she says. "By any standard, that is an appalling death rate." ("Why pregnant women should get the H1N1 flu vaccine")

It is for every pregnant woman to make her own decision about whether to receive H1N1 and seasonal flu shots this year, in consultation with her health provider and her family. For those who are as yet undecided, the comparison of serious adverse effects (0.000005 percent serious side effects amongst those vaccinated versus 0.04 percent mortality in H1N1 infected pregnant women) may be helpful.

Both Health Canada and the US Centers for Disease Control are now recommending that women at all stages of pregnancy be vaccinated. In Canada, it is generally recommended that expectant mothers opt for the unadjuvanted vaccine, but the adjuvanted vaccine has also been declared safe for use during pregnancy. In the United States, pregnant women should only receive the injected vaccine, and not the nasal spray, which contains live attenuated virus.

Protecting Infants by Vaccinating Mothers

In addition to concerns about the effect on unborn children, "Diane Francoeur, chief of obstetrics-gynecology at Ste. Justine Hospital, said some newborns have developed laboratory-confirmed H1N1 flu because their mothers were infected." ("Only half of pregnant women vaccinated against H1N1: health authorities")

Because infants under six months old cannot be vaccinated against influenza, Francoeur says the best way for them to gain immunity is for their mothers to be vaccinated during pregnancy. Having the members of a newborn's household vaccinated is a good way to increase protection, as is keeping the number of visitors relatively small.

If a woman delivers before getting her seasonal or swine flu shot, she should still consider being vaccinated. Breastfeeding women will confer some immunity on their infants. ("2009 H1N1 Influenza shots and pregnant women: Questions and answers for patients")

Relying on Herd Immunity or Antiviral Medications

Only about half of Montreal's pregnant population had been vaccinated for H1N1, as Quebec wound down its mass vaccination campaign. Some women may be hoping to rely on a combination of hygiene precautions and the immunity of those around them. Others may feel that, as long as they receive Tamiflu® or Relenza® if they become infected, they have nothing to worry about.

Do keep in mind that like any medication, both these antivirals have adverse side effects as well. Relenza® (zanamivir) must be inhaled, and may not be safe for some people who have underlying respiratory conditions such as asthma. According to the manufacturer, its side effects include: "headaches; diarrhea; nausea; vomiting; nasal irritation; bronchitis; cough; sinusitis; ear, nose, and throat infections; and dizziness. Other side effects that have been reported, but were not as common, include rashes and allergic reactions, some of which were severe." ("About Relenza")

Tamiflu® (oseltamivir) is distributed in North America by Roche, which warns the drug "is normally not recommended for use during pregnancy or nursing, as the effects on the unborn child or nursing infant are unknown." ("Side effects and safety of Tamiflu") Roche notes that the drug is "generally well tolerated."

A Wikipedia article about the drug states, "Common adverse drug reactions (ADRs) associated with oseltamivir therapy (occurring in over 1% of clinical trial participants) include: nausea, vomiting, diarrhea, abdominal pain, and headache. Rare ADRs include: hepatitis and elevated liver enzymes, rash, allergic reactions including anaphylaxis, and Stevens-Johnson syndrome." It goes on to name other side effects "reported in postmarketing surveillance including: toxic epidermal necrolysis, cardiac arrhythmia, seizure, confusion, aggravation of diabetes, and haemorrhagic colitis." There is also concern about neuropsychiatric side effects, including delirium and hallucinations that have led to injury or death. While these side effects have been noted in adults, they are more prevalent in children and teens. Finally, there have been a small number of H1N1 samples that have shown resistence to Tamiflu®. ("Oseltamivir")

As for relying on the immunity of the people in one's entourage this is not practical with influenza in general, particularly when it comes to a novel strain such as H1N1/09. The herd immunity threshold has been estimated as being about 70 to 80 percent, ("Study: Vaccination of 70 percent of US population could control swine flu pandemic", "Is the flu virus mutating dangerously?") and figures reported earlier this month show only about one third of Canadians have opted for the vaccine - too low for herd immunity to be reliable. ("H1N1 vaccine uptake hits range for seasonal shots - roughly 1 in 3 protected")

H1N1: What's a Woman to Do?

None of this is to say that a woman must be vaccinated against either H1N1 or seasonal flu, but that it should be a serious consideration. Women who consulted with their health providers when the vaccine first became available and were told not to be vaccinated may want to follow up, and ask if anything has changed in the meantime.

In recommending a course of action, doctors always weigh its benefits against its potential risks. More information has become available about the safety of H1N1 vaccine and about the risk H1N1 influenza poses to women in later pregnancy. This information may result in different advice today, than was given weeks or months ago. Any woman who opts not to receive the vaccine should discuss this choice with her doctor or midwife, and should seek advice for lowering her risks at holiday celebrations.

Mass Vaccination Clinics Closed: It's Still Not Too Late to Get Vaccinated!

Almost all of Quebec's mass vaccination clinics are now closed, but H1N1 vaccine is still available to residents at no charge. Visit the list of vaccination centers on the Pandémie Québec web site. Quebec will continue to offer H1N1 vaccines into the month of January. Seasonal flu vaccination begins early January. Those who wish to receive a seasonal flu shot should consult their health provider.

Preventive Leave for Expectant Mothers in Quebec

Women whose employment puts them at risk during their pregnancy can be granted a preventive leave or a job reassignment where this is possible. See this article for more information about preventive leave, as it relates to the swine flu pandemic.

Kyla Matton is a freelance writer and homeschooling mother of four. Having worked for close to a decade in health care, Kyla feels very strongly that individuals should be informed before making health care choices. The information in this article is not intended to replace medical advice, but rather as a starting point for exploration of this important concern. Please make personal health decisions after exploring all available data, and in consultation with a trusted health expert.

Sources:

"2009 H1N1 Influenza shots and pregnant women: Questions and answers for patients" CDC

"About Relenza" GlaxoSmithKline

"Backgrounder: Vaccine myths" Public Health Agency of Canada

"H1N1 vaccine uptake hits range for seasonal shots - roughly 1 in 3 protected" Helen Branswell (Canadian Press)

"Influenza" Wikipedia

"Influenza vaccination during pregnancy" Ran Goldman M.D. and Gideon Koren M.D. (Motherisk, Toronto Hospital for Sick Children)

"Information on pregnancy, breastfeeding and H1N1 flu virus" Public Health Agency of Canada

"Is the flu virus mutating dangerously?" Andre Picard (Globe and Mail)

"Only a handful of serious side effects from H1N1 vaccine" CTV News

"Only half of pregnant women vaccinated against H1N1: health authorities" Aaron Derfel (The Gazette)

"Oseltamivir" Wikipedia

"Pandemic H1N1/09 virus" Wikipedia

"Side effects and safety of Tamiflu" Roche

"Study: Vaccination of 70 percent of US population could control swine flu pandemic" PhysOrg News

"Unadjuvanted H1N1-2009 influenza vaccine: Fact sheet for pregnant women" Ontario Ministry of Health and Long-Term Care

"The vaccination campaign will continue under new terms and conditions" Organisation de la sécurité civile du Québec, news release

"Severe reactions to H1N1 vaccine in Canada: WHO" Agence France-Presse

"Why pregnant women should get the H1N1 flu vaccine" Amy Tuteur M.D.