Flu Vaccination in Pregnancy

Transcription

1 Flu Vaccination in Pregnancy An Update for Midwifery August 2018 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 2018/19 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 0

2 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. * ** 0

3 2018/19 Programme From September 2018 all pregnant women will be offered quadrivalent inactivated influenza vaccine, containing two subtypes of influenza A and two subtypes of influenza B Page 1 Updates to this resource: Changes to notes to reflect product change from trivalent to quadrivalent, updates to graphs and charts with latest pregnancy and vaccine uptake figures 1

4 Aims of resource To support staff involved in discussing flu vaccination with pregnant women by providing evidence based information To promote increased uptake of flu vaccination in pregnant women through increased awareness and understanding amongst midwives of the importance of getting vaccinated against flu whilst pregnant Page 2 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. 2

5 Learning outcomes After completing this resource a midwife will be able to: Understand their role in raising the issue of flu vaccination with all women in the antenatal period and providing women with evidence based information about flu vaccination Describe the aetiology of flu Have an understanding of how flu is transmitted and the possible effects of influenza on pregnant women and neonates Discuss the important role of flu vaccination in relation to pregnant women Be aware of sources of additional information Page 3 3

6 Contents 1. What is flu? 2. Flu vaccination and pregnant women 3. Flu vaccines 4. The role of midwifery 5. Resources Page 4 4

7 What is flu? Flu or as it is sometimes known influenza is a highly infectious viral illness In the main flu is self limiting but in pregnancy may result in complications for the mother and baby Page 5 In the main flu is self limiting but in pregnancy may result in complications for the mother and baby 5

8 Flu viruses There are 3 types of flu viruses Page 6 There are three types of influenza 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. From September 2018 all pregnant women will be offered quadrivalent inactivated influenza vaccine, containing two subtypes of influenza A and two subtypes of influenza B 6

9 Influenza A virus Genetic material (RNA) in the centre Two surface antigens: Haemagglutinin (H) Neuraminidase (N) Different types of each Page 7 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 7

10 Genetic change what this means Antigenic drift small constant mutations of H and N occurs in all types of flu virus Page 8 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 8

11 Antigenic shift Only occurs in type A A major change in one or both surface antigens, characteristic of type A influenza viruses It is due to genetic recombination when virus particles of more than one strain infect a cell simultaneously It can result in a worldwide pandemic Page 9 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 It will happen again! 9

12 Features of flu Transmitted by large droplets and smallparticle aerosols Incubation period 1 5 days (average 2) Acute viral infection of respiratory tract Common symptoms include: Sudden onset of fever, chills, headache, myalgia and severe fatigue Dry cough, sore throat and stuffy nose Page 10 In healthy individuals it is usually unpleasant but self limiting with recovery within 5 7 days. 10

13 Possible complications Bronchitis Secondary bacterial pneumonia Otitis media (children) Meningitis, encephalitis Most serious illness in neonates, pregnant women, older people and those with underlying disease Page 11 11

14 Flu vaccination In Scotland there is an annual vaccination programme which aims to reduce the impact (morbidity and mortality) of flu particularly in high risk groups e.g. pregnant women The vaccine is modified each season to ensure the best protection for risk groups The vaccine is offered between September and end March in any flu season For a small number of pregnant women whose pregnancy spans the end of one winter season and the beginning of the next this may mean that they are vaccinated twice in their pregnancy Page 12 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. 12

15 80.0% Seasonal Influenza Vaccine Uptake 2017/18 compared with 2016/17 Pregnant at risk versus no risk in Scotland Pregnant/no risk Pregnant/at risk WHO Target Pregnant/no risk Pregnant/at risk % 60.0% Vaccine Uptake (%) 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% Week Page 13 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. Four 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 13

16 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), data source HPS pregnant women were recorded 2017/18 (compared to 44090, 2016/17). This compares with the ISD estimate: April 2017 March 2018: births NRS registered. Vaccine uptake in pregnant women at risk in 2017/2018 was higher than in previous season: Pregnant at risk: 61.8% (compared to 58% in 2016/17) Pregnant no risk: 48.1% (compared to 49.3% in 2016/17) 13

17 Flu vaccination and pregnant women What is the evidence to support the offer of vaccination? Page 14 The following slides give you some information about the risk from both seasonal influenza and H1N1 in pregnancy. 14

18 Why vaccinate pregnant women? Immune system alters in pregnancy biased towards innate immunity to prevent rejection of fetus Reduction in cell mediated immunity in order to prevent harm to fetus Pregnant women are predisposed to influenza infection due to the physiological changes and immune function in pregnancy such as increased heart rate, stroke volume, and oxygen consumption: a decrease in lung capacity; and alterations in cell mediated immunity Page 15 During pregnancy there are significant changes in the immune system which may result in increased susceptibility or increased complications from infections including flu. 15

19 Why vaccinate pregnant women? (contd.) Hormonal changes Rise in total cell count Depression in lymphocyte function Depression in cytokine activity Suppression of chemotaxis Delayed/decreased response to infections, especially herpes, influenza, rubella, hepatitis, polio and malaria Page 16 16

20 Why vaccinate pregnant women? Flu poses a unique risk to pregnant women: Annual global attack rate: 5 10% in adults 20 30% in children Women of child bearing age at more risk due to contact with children Page 17 17

21 Why vaccinate pregnant women? Several epidemiological studies report increased rates of influenza associated disease in pregnant women compared with non pregnant Every year in Scotland, a number of pregnant women will get flu, some of which will require hospitalization and intensive care management, particularly in seasons in which H1N1 is the main circulating strain (in the 2015/16 season 5 women were admitted to ITU with SARI) Page 18 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 18

22 Risk to pregnant women Risk appears to increase as pregnancy progresses Hospitalised pregnant women with respiratory illness had higher odds of pre term delivery, fetal distress, caesarean section Pregnant women have consistently been found to be at a higher risk for morbidity and mortality from both seasonal and pandemic influenza compared to non pregnant adults. All pregnant women (regardless of the presence of comorbidities) are at a higher risk for hospital admission related to flu compared to non pregnant women with comparable age and health, with the magnitude of increased risk ranging from four to 18 fold. Increased risk of adverse outcomes for fetuses/neonates born to women affected by flu during pregnancy Page 19 Mak TK et al (2008) Influenza vaccination in pregnancy: current evidence and selected national policies. Lancet Infectious Diseases 8: 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: 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): 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:

23 Recent observation/studies relating to flu and pregnant women Strength of evidence falls into two categories: Good and limited Page 20 In the following slides we will summarise the evidence to newer published information on this topic 20

24 Recent observations/studies Where the strength of evidence is Good Observation Increased risk from complications if they contract flu* A number of studies show that flu vaccination during pregnancy provides passive immunity against flu to infants in the first six months of life** Further detail regarding the evidential base can be found at the NES weblink Seasonal Flu Page 21 Further detail regarding the evidential base can be found at and training/bytheme initiative/publichealth/health protection/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 Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Am J Epidemiol, 148, (11) available from: 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 Pandemic Influenza A (H1N1) 2009 and mortality in the United Kingdom: risk factors for death, April 2009 to March Euro Surveill, 15, (20) available from: 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 The Comparative Clinical Course of Pregnant and Non Pregnant Women Hospitalised with Influenza A(H1N1)pdm09 Infection. PLoS One, 7, (8) e41638 available from: pubmed/ ?dopt=citation 21

25 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: Benowitz I, Esposito DB, Gracey KD, Shapiro ED, Vázquez M. Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis. 2010;51: Pierce, M., Kurinczuk, J.J., Spark, P., Brocklehurst, P., & Knight, M Perinatal outcomes after maternal 2009/H1N1 infection: national cohort study. BMJ, 342, d3214 available from: ncbi.nlm.nih.gov/pubmed/ ?dopt=citation McNeil, S.A., Dodds, L.A., Fell, D.B., Allen,V.M., Halperin, B.A., Steinhoff, M.C., & MacDonald, N.E Effect of respiratory hospitalization during pregnancy on infant outcomes. AmJ Obstet Gynecol, 204, (6 Suppl 1) S54 S57 available from: Omer, S.B., Goodman, D., Steinhoff, M.C., Rochat, R., Klugman, K.P., Stoll, B.J., & Ramakrishnan, U Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: a retrospective cohort study. PLoS Med, 8, (5) e available from: Benowitz, I., Esposito, D.B., Gracey, K.D., Shapiro, E.D., & Vazquez, M Influenza vaccine given to pregnant women reduces hospitalization due to influenza in their infants. Clin Infect Dis, 51, (12) available from: 21

26 Recent observations/studies Where the strength of evidence is Good Observation A review of studies on the safety of flu vaccine in pregnancy concluded that inactivated flu vaccine can be safely and effectively administered during any trimester of pregnancy and that no study to date has demonstrated an increased risk of either maternal complications or adverse fetal outcomes associated with inactivated influenza vaccine *** Further detail regarding the evidential base can be found at the NES weblink Seasonal Flu Page 22 Further detail regarding the evidential base can be found at and training/bytheme initiative/publichealth/health protection/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 Maternal influenza vaccination and effect on influenza virus infection in young infants. Arch Pediatr Adolesc Med, 165, (2) available from: 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): Polyzos KA, Konstantelias AA, Pitsa CE, Falagas ME. Maternal influenza vaccination and risk for congenital malformations: a systematic review and metaanalysis. Obstetrics & Gynecology 2015;126(5): 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 (16)

27 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 Jan;122(1): 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. 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.: CD DOI: / CD 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):

28 Recent observations/studies Where the strength of evidence is limited Flu during pregnancy may be associated with premature birth and smaller birth size and weight Flu vaccination may reduce the likelihood of prematurity and smaller infant size at birth associated with influenza infection during pregnancy Further detail regarding the evidential base can be found at andtraining/by theme initiative/public health/healthprotection/seasonal flu/flu vaccination inpregnancy.aspx Page 23 Further detail regarding the evidential base can be found at 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): 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:e Steinhoff MC, Omer SB, Roy E, et al. Neonatal outcomes after influenza immunization during pregnancy: a randomized controlled trial. CMAJ. 2012;184: 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 Effectiveness of maternal influenza immunization in mothers and infants. N Engl J Med, 359, (15) available from: pubmed/ ?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 The underrecognized burden of influenza in young children. N Engl J Med, 23

29 355, (1) available from: 23

30 Risk to fetus Transplacental transmission of flu infection is rare Limited evidence supports an association between infection with flu and development of congenital abnormalities Page 24 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 Review: Hyperthermia and fever during pregnancy. Birth Defects Res A Clin Mol.Teratol., 76, (7) available from: PM:

31 Risk in non pandemic year infants US study average excess hospitalisation associated with flu in infants < 6 months was approximately 1000 per 100,000 Page 25 Data from WHO Position Paper on Influenza vaccines,

32 2009 Pandemic H1N1 epidemiology 440 fatal cases across the UK (April 2009 to March 2010) 10 were pregnant The Risk (RR) of fatal illness for pregnant women was elevated (RR: 7; 95% CI 3 15) compared with women of child bearing age with no risk factors Page 26 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/H1N influenza in England: public health surveillance study. BMJ. 2009;339:b

33 Risk to pregnant women in other pandemics (other than H1N1) mortality associated with pregnancy 50% % of women of child bearing age who died were pregnant; 10% of all deaths were in pregnant women Page 27 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. 27

34 Flu vaccination Page 28 28

35 Vaccine effectiveness Antibody response is similar in pregnant and non pregnant women Cochrane review vaccine prevents 67% of serologically confirmed and 23% of clinically apparent cases in non pregnant healthy adults High placental transfer of vaccine acquired antibodies (IgG) Page 29 Demicheli V, Rivetti D, et al (2004) Vaccines for preventing influenza in healthy adults. Cochrane Database Syst Rev. 3: CD There is also the mention of studies indicating that the quadrivalent vaccine is likely to be cost effective compared with the trivalent vaccine (Meir et al 2015.,Thommes et al 2015). And that there is an increased health benefit to be gained by the use of quadrivalent vaccines in at risk adults under 65 years of age, including pregnant women (Thorrington et al., 2017). Meier G, Gregg M, Poulsen Nautrup B. Cost effectiveness analysis of quadrivalent influenza vaccination in at risk adults and the elderly: an updated analysis in the U.K. J Med Econ. 2015;18(9): Thommes EW, Ismaila A, Chit A, Meier G, Bauch CT. Cost effectiveness evaluation of quadrivalent influenza vaccines for seasonal influenza prevention: a dynamic modeling study of Canada and the United Kingdom. BMC Infect Dis Oct 27;15:465 Thorrington D, van Leeuwin E, Ramsay M et al. BMC Medicine (2017) 15:166. DOI /s

36 Vaccine Influenza viruses grown in embryonated hen s eggs Chemically inactivated and purified Inactivated (i.e. the vaccine CANNOT cause influenza illness) On average offers 50% protection but higher in years when well matched Antibody levels may take 10 to 14 days to reach protective levels Page 30 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. From September 2018 all pregnant women will be offered quadrivalent inactivated influenza vaccine, containing two subtypes of influenza A and two subtypes of influenza B 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. 30

37 Contraindications A confirmed anaphylactic reaction to a previous dose of the vaccine A confirmed anaphylactic reaction to any component of the vaccine A confirmed anaphylactic reaction to egg products Page 31 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. A review of studies on the safety of influenza vaccine in pregnancy concluded that inactivated influenza vaccine can be safely and effectively administered during any trimester of pregnancy (Tamma et al., 2009). 31

38 Precautions Acute illness Page 32 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. 32

39 Adverse reactions Pain, swelling, redness at injection site Low grade fever, malaise, shivering, fatigue, headache, myalgia and arthralgia Anaphylaxis very rare Page 33 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 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/H1N vaccine Pandemrix was identified in England consistent with findings first identified in Finland and Sweden. 33

40 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/H1N influenza vaccine: retrospective analysis. BMJ 2013;346: f794. 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: e 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: e

41 Administration The vaccine may only be administered: Against a prescription written manually or electronically by a registered medical practitioner or other authorised prescriber Against a Patient Specific Direction Against a Patient Group Direction Page 34 More information on immunisation administration by nurses and other health professionals is available in chapter 5 of Green Book Immunisation against infectious disease can be found here: by nurses and otherhealth professionals the green book chapter 5 All health care practitioners who administers vaccines should refer to this document at al times. The influenza vaccination programme is in the main delivered in General Practice 34

42 Administration site and route Route intramuscular Site deltoid Site and route can affect both the immunogenicity and reactogenicity of the vaccine Page 35 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. 35

43 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. 35

44 Key Role of midwifery in relation to flu vaccination Raise the issue of flu vaccination with pregnant women Advise all women booking for antenatal care during the flu season (September March) that it is strongly recommended that they are vaccinated 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 Page 36 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) 36

45 Page 37

46 Resources Green Book, available at: Influenza chapter 19 available at: green book chapter 19 SG patient leaflet Patient Group Direction Policy for the Storage and Handling of Vaccines NES website for the evidence base: nhs.uk/education andtraining/by theme initiative/publichealth/healthprotection/seasonal flu.aspx vaccine Page 38 Any healthcare practitioner who administers any vaccine should be familiar with the Green Book available at 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 38