Introduction As pregnant women are at an increased risk of developing severe illness and secondary complications related to influenza infection during pandemic and non pandemic influenza seasons they are strongly advised to take up the offer of the seasonal flu vaccination*. Since the introduction of flu vaccination for pregnant women vaccine uptake has improved but is still lower than the recommended target of 75% for at risk populations set by World Health Organisation as reflected in the Chief Medical Officers seasonal flu vaccination programme 2016/17 communication**. It has been recognised that pregnant women may have particular concerns about the vaccine and that will inform decision making about whether or not to be vaccinated. Midwifery are seen as a key group of healthcare professionals in communicating the benefits of the vaccine and helping to ensure that as many pregnant women as possible are immunised. Rationale for resource This resource is designed to support midwives involved in raising the issue of flu vaccination with all women in the antenatal period and providing women with evidence based information about flu vaccination. This resource does not cover the actual administration techniques involved in flu vaccination. If staff are required to deliver flu vaccinations they should refer to their line manager for alternative training The terms flu and influenza are often used interchangeably. For the purposes of this resource the term flu will be used. *http://www.sehd.scot.nhs.uk/cmo/cmo(2012)06.pdf **http://www.sehd.scot.nhs.uk/cmo/cmo(2016)16amend.pdf 0
Key role of midwives in relation to flu vaccination of pregnant women Raise the issue of flu vaccination with pregnant women. Advise all women booking for antenatal care during the flu season (October March) that it is strongly recommended that they are vaccinated by their General Practice as early as possible in the flu season. Explain the risks of flu in pregnancy, the contraindications to vaccination, the evidence in relation to the effects of vaccination on the woman and neonate. Advise women how they can arrange for vaccination and, where appropriate, the midwife could facilitate the arrangements for the appointment to be vaccinated. Follow up at later antenatal appointments to establish whether the woman has had her flu vaccination. Ensure that the date of seasonal influenza vaccination is recorded on SWHMR (Scottish woman held maternity record) see page 12 Special Features. 1
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In the main flu is self limiting but in pregnancy may result in complications for the mother and baby 4
There are three types of influenza virus, and the seasonal flu vaccine protects against the two main circulating types of A virus, and one B virus. A wide range of animals are known to carry type A and B. The seasonal flu vaccine in any year is designed to protect against the main flu viruses known to be circulating. It generally offers protection against the two main circulating type A viruses, and one type B virus. 5
Schematic model of an influenza A virus. There are two antigens on the surface, as illustrated. The role of the H antigen is to bind to the cells of the host and there are 16 different types of H. The role of the N antigen is to release the virus from the cell surface, and there are 9 different types. The different types of H and N are identified by numbers, hence H1N1 for example 6
It s important to understand that flu viruses are constantly changing, and to appreciate how this happens. Flu viruses lack proof-reading enzymes that maintain the fidelity of RNA replication, and are therefore subject to high rates of mutation. Antigenic drift: Small mutations affecting the H and N antigens occur constantly. When changes enable the virus to multiply in an individual immune to previous strains, the new subtype can reinfect the community. This is because mutants emerge that express surface antigens (Hs and Ns) sufficiently different as to be unable to combine with existing antibody. This is why new flu vaccines have to be developed each year, and why individuals at risk require to be immunised annually 7
Antigenic shift Only occurs in type A. A sudden major change occurs as a result of recombination of different virus cells when they infect the same cell. The new strain can then spread through a population immune to previous strains, and lead to a pandemic. This is what happened in 2009. It will happen again! 8
In healthy individuals it is usually unpleasant but self-limiting with recovery within 5 7 days. 9
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The main measure for reducing the impact (morbidity and mortality) from flu is the annual vaccination programme. The offer of vaccination is restricted to the period from September to the end of March of the following year. Since the immunity to vaccination is specific to the strains in the vaccine, vaccination with last seasons vaccine may not confer immunity in the following season. The seasonal flu vaccine is reformulated each season since the flu viruses circulating in the community may change. For a small number of pregnant women this may mean that they are vaccinated with one vaccine in March and are then re-offered vaccination with a new vaccine in September. Other measures which may assist in reducing the impact from influenza are respiratory hygiene and antiviral medicines. In 2010 JCVI recommended that pregnant women should be included in the risk groups for influenza vaccination. 11
Following the pandemic in 2009, the Joint Committee for Vaccination and Immunisation concluded that pregnant woman were at increased risk of complications of seasonal influenza and should be annually offered the seasonal influenza vaccine. This recommendation was accepted by Scottish Government and each year the Chief Medical Officer sets a target for the uptake of seasonal influenza vaccine. This target is 75% across all of the groups at increased risk of complications (those over the age of 65, those under the age of 65 with chronic medical conditions and pregnant women). To encourage pregnant women to come forward for vaccination every effort should be made by all health practitioners to refer pregnant women to their general practice for the offer of vaccination (In some areas the model of vaccine delivery may be different e.g. midwifery check locally). Seasonal flu vaccination sessions in each practice commence as soon as vaccine becomes available (from early September in some but mainly in October) and pregnant women should be encouraged to be vaccinated as early in the season as possible to offer the best chance of protection. Weekly estimated flu vaccine uptake figures are collated for pregnancy by Health Protection Scotland from each general practice and returned in summary format to each NHS board. For the information to be meaningful the general practice needs to be able to record that their patient is pregnant* (denominator data) and whether they have received the flu vaccine (numerator data). Remote electronic extraction from the general practice allows the collation of such information. *Deductions from this number are made in the unfortunate event of fetal loss etc. Uptake figures over the last two seasons have become increasingly accurate through improved determination of the size of the pregnant population (the denominator). 45063 pregnant women were recorded 2015/16 (compared to 46 434, 2014/15). This compares with the ISD estimate: April 2014-March 2015: 53 976 births NRS registered. However vaccine uptake in pregnant women in 2015/2016 was lower than in previous season: Pregnant at risk: 61.5% (compared to 65% in 2014/15) Pregnant no risk: 49.9% (compared to 49.5% in 2014/15) 12
The following slides give you some information about the risk from both seasonal influenza and H1N1 in pregnancy. 13
During pregnancy there are significant changes in the immune system which may result in increased susceptibility or increased complications from infections including flu. 14
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Englund cites studies which demonstrate more visits to equivalent of GP; and higher risk of hospitalisation for pregnant women. Englund JA (2003) Maternal immunisation with inactivated influenza vaccine: rationale and experience. Vaccine 21: 3460 Infants who contract flu have more severe illness and higher rates of hospitalisation. This will be discussed in the following slides 17
Mak TK et al (2008) Influenza vaccination in pregnancy: current evidence and selected national policies. Lancet Infectious Diseases 8: 44-52. Neuzil K, Reed G, Mitchel E, Simonsen L, Griffin MR. Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Am J Epidemiol. 1998;148:1094 1102. Dodds L, McNeil SA, Fell DB, et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ. 2007;176(4):463 468. Cox S, Posner SF, McPheeters M, Jamieson DJ, Kourtis AP, Meikle S. Hospitalizations with respiratory illness among pregnant women during influenza season. Obstet Gynecol. 2006;107:1315 1322.. 18
In the following slides we will summarise the evidence to newer published information on this topic 19
Further detail regarding the evidential base can be found at http://www.nes.scot.nhs.uk/education-and-training/bytheme-initiative/public-health/healthprotection/seasonal-flu.aspx. Increased risk from complications if they contract flu * Neuzil, K.M., Reed, G.W., Mitchel, E.F., Simonsen, L., & Griffin, M.R. 1998. Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Am J Epidemiol, 148, (11) 1094-1102 available from: http://www.ncbi.nlm.nih.gov/pubmed/9850132?dopt=citation McNeil SA, Dodds LA, Fell DB, et al. Effect of respiratory hospitalization during pregnancy on infant outcomes. Am J Obstet Gynecol. 2011;204(Suppl):S54 S57. Pebody, R.G., McLean, E., Zhao, H., Cleary, P., Bracebridge, S., Foster, K., Charlett, A., Hardelid, P., Waight, P., Ellis, J., Bermingham, A., Zambon, M., Evans, B., Salmon, R., McMenamin, J., Smyth, B., Catchpole, M., & Watson, J. 2010. Pandemic Influenza A (H1N1) 2009 and mortality in the United Kingdom: risk factors for death, April 2009 to March 2010. Euro Surveill, 15, (20) available from: http://www.ncbi.nlm.nih.gov/pubmed/20504388?dopt=citation Dolan, G.P., Myles, P.R., Brett, S.J., Enstone, J.E., Read, R.C., Openshaw, P.J., Semple, M.G., Lim, W.S.,Taylor, B.L., McMenamin, J., Nicholson, K.G., Bannister, B., & Nguyen-Van-Tam, J.S. 2012.The Comparative Clinical Course of Pregnant and Non-Pregnant Women Hospitalised with Influenza A(H1N1)pdm09 Infection. PLoS One, 7, (8) e41638 available from: http://www.ncbi.nlm.nih.gov/ pubmed/22870239?dopt=citation A number of studies show that flu vaccination during pregnancy provides passive immunity against flu to infants in the first six months of life ** Zaman K, Roy E, Arifeen SE, et al. Effectiveness of maternal influenza immunization in mothers and infants. N Engl J Med. 2008;359:1555 1564. Benowitz I, Esposito DB, Gracey KD, Shapiro ED, Vázquez M. Influenza vaccine given to 20
pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis. 2010;51:1355 1361. Pierce, M., Kurinczuk, J.J., Spark, P., Brocklehurst, P., & Knight, M. 2011. Perinatal outcomes after maternal 2009/H1N1 infection: national cohort study. BMJ, 342, d3214 available from: http://www. ncbi.nlm.nih.gov/pubmed/21672992?dopt=citation McNeil, S.A., Dodds, L.A., Fell, D.B., Allen,V.M., Halperin, B.A., Steinhoff, M.C., & MacDonald, N.E. 2011. Effect of respiratory hospitalization during pregnancy on infant outcomes. AmJ Obstet Gynecol, 204, (6 Suppl 1) S54-S57 available from: http://www.ncbi.nlm.nih.gov/ Omer, S.B., Goodman, D., Steinhoff, M.C., Rochat, R., Klugman, K.P., Stoll, B.J., & Ramakrishnan, U. 2011. Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: a retrospective cohort study. PLoS Med, 8, (5) e1000441 available from: http:// www.ncbi.nlm.nih.gov/pubmed/21655318?dopt=citation Benowitz, I., Esposito, D.B., Gracey, K.D., Shapiro, E.D., & Vazquez, M. 2010. Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis, 51, (12) 1355-1361 available from: http://www.ncbi.nlm.nih.gov/pubmed/21058908?dopt=citation 20
Further detail regarding the evidential base can be found at http://www.nes.scot.nhs.uk/education-and-training/bytheme-initiative/public-health/healthprotection/seasonal-flu.aspx. A review of studies on the safety of flu vaccine in pregnancy*** Eick, A.A., Uyeki,T.M., Klimov, A., Hall, H., Reid, R., Santosham, M., & O Brien, K.L. 2011. Maternal influenza vaccination and effect on influenza virus infection in young infants. Arch Pediatr Adolesc Med, 165, (2) 104-111 available from: http://www.ncbi.nlm.nih.gov/pubmed/20921345?dopt=citation Naleway AL, Irving SA, Henninger ML, Li DK, Shifflett P, Ball S, et al. Safety of influenza vaccination during pregnancy: a review of subsequent maternal obstetric events and findings from two recent cohort studies. [Review]. Vaccine 2014 May 30;32(26):3122-7. Polyzos KA, Konstantelias AA, Pitsa CE, Falagas ME. Maternal influenza vaccination and risk for congenital malformations: a systematic review and meta-analysis. Obstetrics & Gynecology 2015;126(5):1075-84. Tapia MD, Sow SO, Tamboura B, et al. Maternal immunisation with trivalent inactivated infl uenza vaccine for prevention of infl uenza in infants in Mali: a prospective, active-controlled, observer-blind, randomised phase 4 trial. Lancet Infect Dis 2016; published online May 31. http://dx.doi.org/10.1016/s1473-3099(16)30054-8. Fell D, Platt R, Lanes A, Wilson K, Kaufman J, Basso O, Buckeridge D. Fetal death and preterm birth associated with maternal influenza vaccination: systematic review. BJOG. 2015 Jan;122(1):17-26. Ludvigsson JF, Strom P, Lundholm C, Cnattingius S, Ekbom A, Ortqvist A, et al. Maternal vaccination against H1N1 influenza and offspring mortality: population based cohort study and sibling design. BMJ 2015;351:h5585. 21
Demicheli V, Jefferson T, Al-Ansary LA, Ferroni E, Rivetti A, Di Pietrantonj C. Vaccines for preventing influenza in healthy adults. Cochrane Database of Systematic Reviews 2014, Issue 3. Art. No.: CD001269. DOI: 10.1002/14651858.CD001269.pub5. McMillan M, Kralik D, Porritt K, Marshall H. Influenza Vaccination During Pregnancy: A Systematic Review Of Effectiveness And Adverse Events. The JBI Database of Systematic Reviews and Implementation Reports; Vol 12, No 6 (2014). Madhi SA, Cutland CL, Kuwanda L, Weinberg A, Hugo A, Jones S, et al. Influenza vaccination of pregnant women and protection of their infants. New England Journal of Medicine 2014;371(10):918-31. 21
Further detail regarding the evidential base can be found at http://www.nes.scot.nhs.uk/education-and-training/bytheme-initiative/publichealth/health-protection/seasonal-flu.aspx. Dodds L, McNeil SA, Fell DB, et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ. 2007;176(4):463 468. Omer SB, Goodman D, Steinhoff MC, et al. Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: a retrospective cohort study. PLoS Med. 2011;8:e1000441. Steinhoff MC, Omer SB, Roy E, et al. Neonatal outcomes after influenza immunization during pregnancy: a randomized controlled trial. CMAJ. 2012;184:645 653. Zaman, K., Roy, E., Arifeen, S.E., Rahman, M., Raqib, R.,Wilson, E., Omer, S.B., Shahid, N.S., Breiman, R.F., & Steinhoff, M.C. 2008. Effectiveness of maternal influenza immunization in mothers and infants. N Engl J Med, 359, (15) 1555-1564 available from: http://www.ncbi.nlm.nih.gov/ pubmed/18799552?dopt=citation Poehling, K.A., Edwards, K.M.,Weinberg, G.A., Szilagyi, P., Staat, M.A., Iwane, M.K., Bridges, C.B., Grijalva, C.G., Zhu,Y., Bernstein, D.I., Herrera, G., Erdman, D., Hall, C.B., Seither, R., & Griffin, M.R. 2006.The underrecognized burden of influenza in young children. N Engl J Med, 355, 22
(1) 31-40 available from: http://www.ncbi.nlm.nih.gov/pubmed/16822994?dopt=citation 22
It is clearly very difficult to obtain evidence as up to half of flu cases are mild or subclinical. In a 2006 review Edwards presented limited evidence on association between infection with flu virus and development of congenital abnormalities. Edwards, M.J. 2006. Review: Hyperthermia and fever during pregnancy. Birth Defects Res A Clin Mol.Teratol., 76, (7) 507-516 available from: PM:16933304 23
Data from WHO Position Paper on Influenza vaccines, 2005. 24
RR = relative risk, i.e., of women who were ill with flu, being pregnant meant the risk of it being fatal was 7 times higher than in healthy non-pregnant women with H1N1. Donaldson LJ, Rutter PD, Ellis BM, Greaves FE, Mytton OT, Pebody RG, et al. Mortality from pandemic A/H1N1 2009 influenza in England: public health surveillance study. BMJ. 2009;339:b5213. 25
In England and Wales in 1957, 12 of 103 women aged 15 to 44 who died from influenza were pregnant. That year flu was the leading cause of maternal mortality, accounting for 20% of maternal deaths. 26
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Demicheli V, Rivetti D, et al (2004) Vaccines for preventing influenza in healthy adults. Cochrane Database Syst Rev. 3: CD001269 28
Due to the changing nature of influenza viruses in February of each year the World Health Organisation recommends the three viruses that should be in the vaccines for the forthcoming winter. Current influenza vaccines are trivalent, containing two subtypes of influenza A and one type B virus. All of the influenza vaccines available in the UK are prepared from viruses grown in fertilised hen s eggs. All but one of the influenza vaccines available in the UK are inactivated. These vaccines do not contain live viruses and cannot cause influenza. One vaccine (Fluenz Tetra ) contains live virus which has been weakened and although it has been adapted so that it cannot replicate in the body, Fluenz-Tetra vaccine is not recommended in pregnancy. None of the vaccines contain thiomersal as a preservative. Protection: On average offers 50% protection but up to 70 to 80% protection when the vaccine strains are well matched to those circulating. Less protective in the elderly, but still significantly reduces bronchopneumonia, hospitalisations and mortality. 29
There are very few individuals who cannot receive any flu vaccine. If there is any doubt specialist advice should be sought on the vaccine and the circumstances under which it could be given. The risk to the individual of not being immunised must be taken into account. Confirmed anaphylaxis is rare. Minor illnesses without fever or systemic upset are not valid reasons to postpone immunisation. If the individual is acutely unwell, immunisation may be postponed until they have recovered. This is simply to avoid confusing the differential diagnosis of any acute illness by wrongly attributing any signs or symptoms to the adverse effects of the vaccine. In the case of postponement due to acute illness a future date for immunisation should be arranged following recovery 30
There are very few individuals who cannot receive any flu vaccine. If there is any doubt specialist advice should be sought on the vaccine and the circumstances under which it could be given. The risk to the individual of not being immunised must be taken into account. Confirmed anaphylaxis is rare. Minor illnesses without fever or systemic upset are not valid reasons to postpone immunisation. If the individual is acutely unwell, immunisation may be postponed until they have recovered. This is simply to avoid confusing the differential diagnosis of nay acute illness by wrongly attributing any signs or symptoms to the adverse effects of the vaccine. In the case of postponement due to acute illness a future date for immunisation should be arranged following recovery. 31
Anaphylaxis is very rare but facilities for its management should be available The following adverse events have been reported very rarely after influenza vaccination over the past 30 years but no causal association has been established: neuralgia, paraesthesiae, convulsions, transient thrombocytopenia, vasculitis with transient renal involvement and neurological disorders such as encephalomyelitis. A study in the UK found that there was no association between Guillain-Barré syndrome (GBS) and influenza vaccines although there was a strong association between GBS and influenza-like illness. The increased risk of GBS after influenza-like illness, if specific to infection with influenza virus, together with the absence of a causal association with influenza vaccine suggests that influenza vaccine should protect against GBS. GBS has been reported very rarely after immunisation with influenza vaccine, one case per million people vaccinated in one US study. However, this has not been found in other studies and a causal relationship has not been established. Narcolepsy/cataplexy. The European Medicines Agency (EMEA) undertook a review of Pandemrix monovalent H1N1 influenza vaccine and narcolepsy in 2011 following an increased number of reported cases of narcolepsy among children and adolescents in Finland and Sweden in the pandemic vaccination programme in late 2009 and early 2010. Side effects and adverse reactions associated with the influenza vaccines Viroflu and Pandemrix have been previously documented. Viroflu (Janssen- Cilag Ltd, formerly Crucell) may be associated with a higher than expected rate of fever in children aged under five years. An increased risk of narcolepsy after vaccination with the ASO3 adjuvanted pandemic A/H1N1 2009 vaccine Pandemrix was identified in England consistent with findings first identified in Finland and Sweden. Viroflu and Pandemrix are no longer used in the UK influenza immunisation programme Notes Miller E, Andrews N, Stellitano L, et al. Risk of narcolepsy in children and young people receiving AS03 adjuvanted pandemic A/H1N1 2009 influenza vaccine: retrospective analysis. BMJ 2013;346: f794. 32
Nohynek H, Jokinen J, Partinen M, et al. AS03 adjuvanted AH1N1 vaccine associated with an abrupt increase in the incidence of childhood narcolepsy in Finland. PLoS One 2012; 7: e33536. Partinen M, Saarenpaa-Heikkila O, Ilveskoski I, et al. Increased incidence and clinical picture of childhood narcolepsy following the 2009 H1N1 pandemic vaccination campaign in Finland. PLoS One 2012; 7: e33723. 32
More information on immunisation by nurses and other health professionals is available in chapter 5 of Green Book (Immunisation against infectious disease) The influenza vaccination programme is in the main delivered in General Practice 33
Most of the inactivated influenza vaccines should be given by intramuscular injection preferably into the deltoid area of upper arm. One brand (Intanza ) is administered by intradermal injection. Immunogenicity = how effectively the vaccine causes the immune system to respond Studies have demonstrated that vaccines are not as immunogenic when injected into subcutaneous fat as they are when injected into muscle, (Zuckerman, 2000). In particular, lower antibody responses to hepatitis B vaccine have been demonstrated when the vaccine is given into the buttock rather than the deltoid muscle, ( Shaw et al 1989). There is evidence that many injections intended to reach the gluteus maximus muscle are actually delivered into fat. Fat is poorly supplied with phagocytes and antigen-presenting cells; there is therefore delay in processing the antigens and in presentation to the T and B cells. It is also believed that some antigens may be denatured by enzymes if they remain in fat for too long. In contrast, when the vaccine is administered IM, it is circulated far more quickly because of the abundant blood supply to muscles. The blood supply to the deltoid muscle is 17% more than to the gluteal muscle, ( Campbell 1995). This is therefore the ideal site for vaccination in children over the age of 12 months. In younger infants, the deltoid is not sufficiently developed, and the vastus lateralis (anterolateral aspect of the thigh) should be used. Reactogenicity Regan et al (2015) evaluated reactogenicity of trivalent influenza vaccine and found no evidence suggesting pregnant women are more likely to report adverse events following influenza vaccination when compared to non-pregnant female healthcare workers of similar age, and in some cases, pregnant women reported significantly fewer adverse events. It is essential to use the correct length and gauge of needle, and an appropriate technique to ensure that the vaccine is correctly delivered to muscle. 34
It is important that the offer of vaccination and advice are documented in SWHMR (and any electronic hospital record). Advise women and document within SWHMR ( and any electronic hospital record) how they can arrange for vaccination and where appropriate, the midwife could facilitate the arrangements for the appointment to be vaccinated. Follow up at a later antenatal appointments to establish whether the woman has had her flu vaccination (Ensure that the date of seasonal flu vaccination is recorded on SWHMR (Scottish woman held maternity record) 35
Any healthcare practitioner who administers any vaccine should be familiar with the Green Book available at http://www.dh.gov.uk/greenbook Part 1 includes 12 chapters the content of which is generic, and midwives should be familiar with the content. They should also be very familiar with the chapter specific to flu vaccine, and be advised to print a copy. NB The Green Book was last published as a hard copy in 2006, but most chapters have undergone significant updating since then and therefore the electronic version should always be consulted 36