DRAFT ONLY - Please see the disclaimer text on slide 1 Seasonal influenza – prevention and control measures 8th January 2018 Sam Perkins Principal Health Protection Practitioner, South London Health Protection Team, and PHE London Influenza Lead
DRAFT ONLY - Please see the disclaimer text on slide 1 Flu overview flu is an acute viral infection of the respiratory tract (nose, mouth, throat, bronchial tubes and lungs) it is a highly infectious illness which spreads rapidly in closed communities easily transmitted by large droplets, small-particle aerosols and by hand to mouth/eye contamination from a contaminated surface or respiratory secretions of infected person incubation period 1-5 days (average 2-3 days) though may be longer especially in people with immune deficiency in healthy individuals, flu is usually unpleasant but self-limiting with recovery within 2-7 day people with mild or no symptoms can still infect others most cases in the UK occur during an 8 to 10 week period during the winter The national flu immunisation programme 2014/15
DRAFT ONLY - Please see the disclaimer text on slide 1 Influenza viruses A viruses cause outbreaks most years and are the usual cause of epidemics live and multiply in wildfowl from where they can be transmitted to humans also carried by other mammals B viruses tend to cause less severe disease and smaller outbreaks predominantly found in humans burden of disease mostly in children
Flu A virus Schematic model of a flu A virus. Genetic material (RNA) in the centre Two surface antigens: Haemagglutinin (H) (blue) Neuraminidase (N) (red) There are 18 different types of H and 11 different types of N Schematic model of a flu 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. There are 18 different types of H. The role of the N antigen is to release the virus from the cell surface. There are 11 different types of N. The different types of H and N are identified by numbers, hence H1N1 or H3N2 for example. The role of haemagglutinin is to bind to the cells of the infected person The role of neuraminidase is to release the virus from the cell surface
Genetic changes in the flu virus – what this means DRAFT ONLY - Please see the disclaimer text on slide 1 Genetic changes in the flu virus – what this means Changes in the surface antigens (H and N) result in the flu virus constantly changing antigenic drift: minor changes (natural mutations) in the genes of flu viruses that occur gradually over time antigenic shift: when two or more different strains combine. This abrupt major change results in a new subtype. Immunity from previous flu infections/vaccinations may not protect against the new subtype, potentially leading to a widespread epidemic or pandemic Because of the changing nature of flu viruses, WHO monitors their epidemiology throughout the world. Each year WHO makes recommendations about the strains of influenza A and B which are predicted to be circulating in the forthcoming winter. These strains are then included in the flu vaccine developed each year The World Health Organization (WHO) convenes a group that reviews the global influenza situation (once each year for the northern hemisphere and once for the southern hemisphere) and recommends which flu strains should go in the seasonal vaccine to be produced by manufacturers for the following season six to eight months later. This recommendation is based on information about the circulating viruses and epidemiological data from around the world at that time. Most current influenza vaccines are trivalent, containing two subtypes of influenza A and one B virus. Quadrivalent vaccines with an additional B virus have been developed and the first authorised quadrivalent flu vaccine was made available for use in the UK in 2013. The use of quadrivalent flu vaccines containing a B strain from each of the two B strain lineages is expected to improve the matching of the vaccine to the circulating B strain(s).
Signs and symptoms Influenza is more than “a bit of a cold”! fever headache tiredness cough sore throat runny nose myalgia diarrhoea and vomiting (more common in children) ***** the £20 challenge! Complications: Common – bronchitis, otitis media (children), sinusitis, secondary bacterial infection Less common – meningitis, encephalitis, primary influenza pneumonia Influenza is more than “a bit of a cold”!
Seasonal Influenza - annual challenge 1. What ? Different flu strains circulate each year 3. How much ? Variable amounts of flu will occur 2. When ? The start of the flu season can vary by 4-5 months 4. Who ? Attack rates by age, and mortality depend on the circulating strains OCTOBER DECEMBER FEBRUARY Slide courtesy: Dr Richard Peabody, PHE
Flu vaccine eligibility: 2017/18 flu season all those aged two and three (but not four years or older) on 31 August 2017 (ie date of birth on or after 1 September 2013 and on or before 31 August 2015) all children in reception class and school years 1, 2, 3 and 4 all primary school-aged children in former primary school pilot areas people aged six months to under 65 years in clinical risk groups morbidly obese patients (BMI >40) all pregnant women (including those who become pregnant during flu season) people aged 65 years and over (including those becoming 65 years by 31 March 2018) people living in long-stay residential care homes or other long-stay care facilities carers and household contacts of immunocompromised individuals Frontline health and social care workers with direct patient/service user contact should be provided with flu vaccination by their employer. This includes staff in all NHS trusts (including ambulance trusts), general practices, care homes, and domiciliary care “Long stay care facilities” does not include prisons, young offender institutions, or university halls of residence “Carers” are those who are in receipt of a carer’s allowance, or those who are the main carer of an older or disabled person whose welfare may be at risk if the carer falls ill Consideration should also be given to the vaccination of household contacts of immunocompromised individuals, specifically individuals who expect to share living accommodation on most days over the winter and, therefore, for whom continuing close contact is unavoidable This list is not exhaustive, and the healthcare practitioner should apply clinical judgement to take into account the risk of flu exacerbating any underlying disease that a patient may have, as well as the risk of serious illness from flu itself. Flu vaccine should be offered in such cases even if the individual is not in the clinical risk groups specified above
Flu immunisation should also be offered to: those living in long-stay residential care homes or other long-stay care facilities where rapid spread is likely to follow introduction of infection and cause high morbidity and mortality (this does not include prisons, young offender institutions, university halls of residence etc) those who are in receipt of a carer’s allowance, or those who are the main carer of an elderly or disabled person whose welfare may be at risk if the carer falls ill household contacts of immunocompromised individuals, specifically those who expect to share living accommodation on most days over the winter and therefore for whom continuing close contact is unavoidable health and social care staff in direct contact with patients/service users should be vaccinated as part of an employer’s occupational health obligation
Flu vaccine uptake rates 2015/16 – 2016/17 2016/17 2015/16 Uptake ambition 2017/18 Patients aged 65 years or older 70.5% 71.0% 75% Patients aged six months to under 65 years in risk groups (excluding pregnant women without other risk factors) 48.6% 45.1% 55% (maintain higher rates where this has already been achieved) Pregnant women 44.9% 42.3% Health care workers 63.2% 50.6% Children aged two years old (including those in risk groups) 38.9% 35.4% 40-65% (eligible children aged 2 to 8 years) Children aged three years old (including those in risk groups) 41.5% 37.7% Children aged four years old (including those in risk groups) 33.9% 30.0% The long-term ambition is that in most eligible groups for whom flu vaccination provides direct protection, a minimum 75% flu vaccine uptake rate is achieved. As the next step to achieving this, vaccine uptake ambitions for 2017/18 are set out in the table above. Flu vaccine uptake rates for the last two years are shown in the table above. Overall uptake increased in all cohorts in England in the 2016/17 flu season with the exception of the 65 year and over group. .
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Key messages flu immunisation is one of the most effective interventions we can provide to reduce harm from flu and pressures on health and social care services during the winter it is important to increase flu vaccine uptake in clinical risk groups because of increased risk of death and serious illness if people in these groups catch flu for a number of years, only around half of patients aged six months to under 65 years in clinical risk groups have been vaccinated influenza during pregnancy may be associated with perinatal mortality, prematurity, smaller neonatal size, lower birth weight and increased risk of complications for mother vaccination of health and social care workers protects them and reduces risk of spreading flu to their patients, service users, colleagues and family members by preventing flu infection through vaccination, secondary bacterial infections such as pneumonia are prevented. This reduces the need for antibiotics and helps prevent antibiotic resistance Morbidity and mortality attributed to flu is a key factor in NHS winter pressures and a major cause of harm to individuals especially vulnerable people. The annual flu immunisation programme helps to reduce GP consultations, unplanned hospital admissions and pressure on A&E and is therefore a critical element of the system-wide approach for delivering robust and resilient health and care services during winter.