{"id":789,"date":"2014-09-18T15:30:18","date_gmt":"2014-09-18T05:30:18","guid":{"rendered":"http:\/\/www.mvec.vic.edu.au\/?page_id=789"},"modified":"2024-12-17T11:10:16","modified_gmt":"2024-12-17T00:10:16","slug":"%e6%af%8d%e4%ba%b2%e5%9c%a8%e6%80%80%e5%ad%95%e6%9c%9f%e9%97%b4%e6%8e%a5%e7%a7%8d%e7%96%ab%e8%8b%97","status":"publish","type":"references","link":"https:\/\/mvec.mcri.edu.au\/zh\/references\/maternal-vaccination-during-pregnancy\/","title":{"rendered":"Maternal vaccination"},"content":{"rendered":"
<\/p>\n

Background<\/h2>\n

Administering v<\/span>accines <\/span>during a <\/span>pregna<\/span>ncy <\/span>is<\/span> an important way to provide <\/span>much needed <\/span>protect<\/span>ion <\/span>at a time <\/span>when <\/span>a person is<\/span> more vulnerable to <\/span>severe <\/span>disease<\/span> and complications<\/span>. <\/span>Vaccination during pregnancy also ha<\/span>s<\/span> the added benefit of <\/span>allowing the <\/span>transfer<\/span> of maternal<\/span> antibodies across the placenta <\/span>to the unborn baby <\/span>which will <\/span>provide<\/span> short-term<\/span> protection (<\/span>passive <\/span>immunity<\/span>)<\/span> in the first few months of life.<\/span><\/span><\/p>\n

During pregnancy<\/span>,<\/span> m<\/span>any <\/span>anatomical and physical <\/span>changes <\/span>occur t<\/span>o support <\/span>the growth of <\/span>a <\/span>baby<\/span>. <\/span>Some of these changes <\/span>include<\/span> an <\/span>increas<\/span>e in <\/span>blood volume, <\/span>increas<\/span>ed<\/span> demand on the heart <\/span>and lungs<\/span>, <\/span>increas<\/span>ed<\/span> physical pressure <\/span>placed <\/span>on <\/span>other <\/span>organs<\/span> due to an enlarged uterus, <\/span>and changes <\/span>to <\/span>the immune system to ensure that the developing baby is not recognised as \u201cforeign<\/span>\u201d.<\/span> With these changes comes an<\/span> increase<\/span>d<\/span> risk <\/span>of<\/span> experiencing severe symptoms and complications if exposed to infections, in particular respiratory infections<\/span>.<\/span><\/p>\n

The<\/span> administration of <\/span>vaccines <\/span>during pregnancy<\/span> was historically avoided<\/span>. <\/span>However, as <\/span>technologies <\/span>ha<\/span>ve <\/span>advanced<\/span>,<\/span> the benefits that some vaccines can offer when adm<\/span>i<\/span>nistered during p<\/span>re<\/span>gnancy<\/span> now <\/span>far outweigh any <\/span>theoretical <\/span>concerns for safety<\/span>.<\/span> This has been par<\/span>t<\/span>icularly <\/span>evident<\/span> during pandemics such as <\/span>H1N1<\/span><\/a> and <\/span>COVID-1<\/span><\/span>9<\/span><\/a> where pregnant people <\/span>were more likely to experience <\/span>severe disease,<\/span> hospitalisation<\/span> and intensive care<\/span>, <\/span>affecting <\/span>maternal and <\/span>infant <\/span>outcomes<\/span>.<\/span><\/p>\n

Recommendations<\/h2>\n

A thorough assessment of a person\u2019s immunisation history and administration of any outstanding vaccines prior to pregnancy is an important part of preconception care. Administration of live<\/span><\/span>\u2011<\/span><\/span>a<\/span><\/span>ttenuated vaccines<\/a> (e.g. MMR<\/a>\/V<\/a>) during pregnancy is contraindicated due to the theoretical risks associated with vaccine-related disease and its impact on a developing infant (see \u2018Contraindicated vaccines’ below for more information). Live<\/span><\/span>\u2011<\/span><\/span>attenuated <\/span>vaccines should be <\/span>given <\/span>a minimum of 28 days prior to <\/span>conception<\/span>,<\/span> or<\/span> must be withheld until after delivery.<\/span><\/span><\/span><\/p>\n

During pregnancy, there are multiple inactivated vaccines<\/a> recommended and funded on the National Immunisation Program (NIP)<\/a>. Other inactivated vaccines can be administered in special circumstances (e.g. medical risk factors, travel) but are not routinely recommended. Refer to the <\/span>Australian Immunisation Handbook: Vaccines that are not routinely recommended in pregnancy<\/span><\/a> for further information.<\/p>\n

Correctly timing the administration of vaccines during a pregnancy is important and varies with each vaccine. Guidance on timing is based on whether the resulting immune response is intended to protect the mother, the infant, or both.<\/span><\/p>\n

Influenza<\/h3>\n

Influenza<\/a> vaccination during pregnancy is safe and strongly recommended to protect the mother from infection and avoid complications of disease. During pregnancy there is an increased effort required by the lungs. Influenza viruses affect lung tissue meaning infection adds further strain. As a result, pregnant people with influenza infection have a higher likelihood of requiring hospitalisation and intensive care than non<\/span>\u2011<\/span>pregnant people with influenza infection. Influenza infections during pregnancy also increase the risk of preterm birth, babies being born at low birthweight<\/a> and stillbirths.<\/span>\u00a0<\/span><\/p>\n

Antibodies derived from maternal vaccination can also cross the placenta providing some protection to the infant. It is estimated that vaccination during pregnancy can reduce the risk of influenza infection by half in infants less than 6 months of age. This is important because influenza vaccines cannot be administered to infants until they are 6 months of age.<\/span>\u00a0<\/span><\/p>\n

Influenza vaccines are recommended annually and can be given at any time during a pregnancy. If a person is vaccinated before becoming pregnant, they should receive another dose when they are pregnant (minimum 4 weeks between doses). When a pregnancy crosses over influenza seasons, pregnant people are recommended to receive two vaccines, one for each season.\u00a0<\/span>\u00a0<\/span><\/p>\n

Refer to <\/span>MVEC: Influenza<\/span><\/a> for up<\/span>\u2011<\/span>to<\/span>\u2011<\/span>date information on current influenza vaccines.<\/span><\/p>\n

Pertussis<\/h3>\n

Pertussis<\/a> vaccination during pregnancy is safe and effective and is recommended to protect both the pregnant person and, most importantly, the infant.<\/span><\/p>\n

Infants under 6 months of age infected with pertussis have the highest rates of hospitalisation and death compared with people infected in other age groups. Symptoms include periods of intense coughing (paroxysmal coughing) with apnoea where infants stop breathing for a short period. There can be vomiting and difficulty feeding due to prolonged paroxysmal coughing episodes. Complications of pertussis in infants include pneumonia (lung infection), seizures and encephalitis (brain inflammation) which can be fatal.<\/span>\u00a0<\/span><\/p>\n

Infants require a 3<\/span>\u2011<\/span>dose course of pertussis vaccines (doses given at 6 weeks, 4 months and 6 months) to be considered fully protected. Vaccination during pregnancy can reduce the likelihood of infections occurring in infants who are too young to have completed this course by 90%.<\/span>\u00a0<\/span><\/p>\n

A single dose of vaccine (which is provided in combination with diphtheria<\/a> and tetanus<\/a>) should be administered between 20 and 32 weeks of gestation, in every pregnancy (including pregnancies that are closely spaced). If the pregnant person was vaccinated prior to pregnancy, they should still receive another vaccine within the pregnancy to ensure the infant will be passively protected. If an infant is born within 2 weeks of their mother’s vaccine, the passive immunity passed onto the infant may be suboptimal.<\/span>\u00a0<\/span><\/p>\n

Refer to <\/span>MVEC<\/span><\/a>: Pertussis<\/a> for further information.<\/span><\/p>\n

Respiratory syncytial virus (RSV)<\/h3>\n

Vaccination against RSV<\/a> during pregnancy is recommended to provide passive immunity to infants. From 2025, vaccination during pregnancy will be funded on the NIP.<\/span>\u00a0<\/span><\/p>\n

Current data shows that almost all children will be infected with RSV by the time they turn 2 years old. <\/span>Whilst most infections are mild, bronchiolitis (inflammation of the small airways) and pneumonia (lung infection) can occur and may lead to hospitalisation for supportive measures such as oxygen therapy and rehydration. I<\/span>nfants with specified risk factors<\/a> such as preterm birth, cardiac conditions and chronic lung disease are more likely to experience severe disease. Clinical trials demonstrate that when vaccines are administered during pregnancy the risks of hospitalisation due to severe RSV infection is reduced by 57% in infants less than 6 months of age. <\/span>\u00a0<\/span><\/p>\n

A single dose of <\/span>Abrysvo <\/span><\/b>should be administered between 28 and <\/span>36 weeks\u2019 gestation (NB: Arexvy is <\/span>not <\/span><\/b>registered for use in pregnancy). There is currently no recommendation for further doses in subsequent pregnancies; however, this may change as more data becomes available. When a pregnant person is vaccinated within 2 weeks of delivery, infant protection is likely to be reduced (many jurisdictions are funding infant RSV prevention programs for infants with medical risk factors and those with suboptimal passive protection).<\/span>\u00a0<\/span><\/p>\n

For more information refer to MVEC: RSV<\/a>.<\/span><\/p>\n

Contraindicated vaccines<\/h2>\n

The RSV vaccine Arexvy must <\/span>not <\/span><\/b>be administered to pregnant women due to a lack of safety and efficacy data. Should inadvertent administration occur, it should be reported to the\u202fadverse event reporting service<\/a>\u202fin your jurisdiction and the patient should be informed using the open disclosure<\/a>\u00a0process.<\/span><\/p>\n

All live-attenuated vaccines are <\/span><\/span>contraindicated<\/span><\/span> during pregnancy due to the potential risk to the unborn baby. In most circumstances the risk is hypothetical<\/span>;<\/span> however, there is insufficient evidence to support vaccination in this patient group.<\/span><\/span><\/p>\n

If a live<\/span><\/span>\u2011<\/span><\/span>attenuated vaccine is <\/span>inadvertently administered<\/a> to <\/span>a pregnant person, the<\/span> person should be informed of the administration error and reassured using the <\/span>open disclosure <\/span><\/a>framework. <\/span><\/span>The <\/span><\/span><\/span>limited safety data<\/span><\/span><\/span> from inadvertent administration of MMR and varicella vaccines is reassuring. <\/span><\/span><\/span>The <\/span>administration error should be <\/span>reported <\/span>to t<\/span>he <\/span><\/span>adverse event reporting service<\/span><\/span><\/a> in your <\/span>jurisdiction<\/span>.<\/span><\/span><\/p>\n

Table 1: Live\u2011<\/span><\/span>attenuated vaccines contraindicated in pregnancy<\/span><\/span><\/strong><\/p>\n<\/div>\n\t

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