An Update for Midwifery July 2019

1. An Update for Midwifery July 2019 • Flu Vaccination in Pregnancy

2. Seasonal Flu Vaccination Programme 2019/20 From September 2019 all pregnant women will be offered quadrivalent inactivated influenza vaccine, containing two subtypes of influenza A and two subtypes of influenza B

3. 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

4. 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

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

6. 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

7. Flu viruses There are 3 types of flu viruses

8. Influenza A virus • Genetic material (RNA) in the centre • Two surface antigens: • Haemagglutinin (H) • Neuraminidase (N) • Different types of each

9. Genetic change – what this means Antigenic drift • small constant mutations of H and N • occurs in all types of flu virus

10. 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

11. Features of flu • Transmitted by large droplets and small-particle 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

12. 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

13. 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

14. Flu vaccination and pregnant women What is the evidence to support the offer of vaccination?

15. 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

16. 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

17. 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

18. 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 

19. Risk to pregnant women • 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 • Risk appears to increase as pregnancy progresses • Hospitalised pregnant women with respiratory illness had higher odds of pre-term delivery, foetal distress, caesarean section  • 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 foetuses/neonates born to women affected by flu during pregnancy 

20. Recent observation/studies relating to flu and pregnant women • Strength of evidence falls into two categories: • Good and limited

21. 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 NES Seasonal Flu

22. 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

23. 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

24. Risk to fetus • Transplacental transmission of flu infection is rare • Limited evidence supports an association between infection with flu and development of congenital abnormalities

25. Risk in non-pandemic year – infants US study - average excess hospitalisation associated with flu in infants < 6 months was approximately 1000 per 100,000

26. 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

27. Risk to pregnant women in other pandemics (other than H1N1) • 1918-1919 • mortality associated with pregnancy – 50% • 1957 • 50% of women of child-bearing age who died were pregnant; 10% of all deaths were in pregnant women

28. Flu vaccination

29. Vaccine effectiveness • Antibody response is similar in pregnant and non pregnant women • Cochrane review – Influenza vaccines against ILI in pregnant women 24%, no significant effect on abortion or neonatal death* • Moderate protection against laboratory-confirmed influenza-associated hospitalization during pregnancy** • High placental transfer of vaccine acquired antibodies (IgG)

30. Vaccine • Influenza viruses grown in embryonated hen’s eggs or cell culture • 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

31. 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

32. Precautions Acute illness

33. Adverse reactions • Pain, swelling, redness at injection site • Low grade fever, malaise, shivering, fatigue, headache, myalgia and arthralgia • Anaphylaxis – very rare

34. 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

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

36. 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

38. NHS Inform • NHS Education for Scotland • Health Protection Scotland • Green Book Chapter 19 • Guidance on Vaccine Storage and Handling • CMO Letter • Patient Group Directions • Resources