Title: Core Topic 1
1Core Topic 1
The aims of immunisation national policy and
schedules
2Learning Outcomes
- To be able to explain the aims of immunisation,
describe national policy and schedules and deal
with variations to the schedule
3Learning Objectives
- Explain the different factors that inform vaccine
policy decisions - Access current vaccine policy
- Describe the current UK vaccine schedule
- Describe how immunisation programmes are
monitored through the use of surveillance and the
COVER programme
4Public health
- The two public health interventions with the
greatest impact are clean water and vaccination - Vaccination is the most effective medical
intervention in the world
5History of Vaccination
- Historical recordings of attempts of vaccination
from 7th century but not really recognised or
successful until - 1796 Edward Jenner demonstrated that inoculation
with cowpox virus produced protection from
infection with smallpox. - (Hence Vaccination taken from vacca the
latin word for cow) - 1860s-1890s Louis Pasteur produced vaccines
against chickenpox, cholera, diphtheria, anthrax
and rabies - Early 20th Century toxoid vaccines against
diphtheria and tetanus produced following
discovery of effective inactivation with
chemicals - Post World War 2 successful live viral vaccines
developed using cell culture techniques - Present and future new technologies constantly
developing recombinant protein vaccines, DNA and
conjugate vaccines
6Components of vaccination programmes
Vaccine delivery - supply, clinics
Vaccine development
Communication
Surveillance of coverage
Monitoring attitudes to vaccination
Policy development
Surveillance of population susceptibility
Adverse events surveillance
Predicting the future - modelling
Surveillance of diseases
7Development of a vaccination programme
- The aim of a vaccination programme is to control
a disease successfully - Before designing a vaccine programme, important
to establish - Is there a need for the programme?
- i.e. does the disease cause a significant
public health problem? - Is a suitable vaccine available that is safe and
effective?
8New vaccines for UK children? Definite or
probable
- Newer vaccines for diseases already targeted in
the childhood programme - inactivated polio vaccine (IPV)
- acellular pertussis vaccine (aP) 5 components
- New combinations of existing vaccines
- DTaP/Hib/IPV (Paediacell)
- Men C / Hib
9New vaccines for UK children?Probable or possible
- More widespread use of vaccines already used
selectively - hepatitis B
- varicella vaccine
- Vaccines where the need is not yet established
- influenza vaccines for children
10New vaccines for UK children?Not yet clear
- Vaccines where there is no current UK need
- Meningococcal ACWY conjugate vaccines
- Vaccines where development of effective vaccines
has been problematic - Eg. Vaccines against group B meningooccus
- Vaccines where safety concerns have been raised
- Eg. rotavirus
11Establishing the need for a vaccination programme
- Disease incidence
- Age distribution
- Trends
- Disease complications
- Mortality
- These are ascertained by surveillance and also
through published literature and special studies
12Hepatitis B vaccine policy
- Current policy
- Selective vaccination of high risk groups
- Antenatal screening and vaccination of infants
born to positive mothers - Additional policy options
- Universal vaccination of adolescents
- Universal vaccination of children
- Geographically selective policy
- Combination of the above
13Acute HBV laboratory reports to CDSCBy age
group, 1990-2002
14Objectives of surveillance
- Surveillance needs to be carried out both before
and after a vaccine programme is introduced - Pre-implementation of vaccine
- To estimate burden of disease
- To decide vaccination strategy
- Post implementation of vaccine
- To monitor effectiveness of vaccine strategy
15Reported acute HBV infections by exposure
category (n675/yr)
16Surveillance for Vaccine Programmes
- Disease incidence
- Reports of disease from a variety of sources are
collated by the Centre for Infections (CfI) - Susceptibility
- Residual blood samples used for serological
surveillance - Vaccine Coverage
- Vaccine uptake monitored across the country,
collated by CfI from local Child Health Computers - Monitoring adverse events and vaccine safety
- Collated by Medicines and Healthcare products
Regulatory Agency (MHRA) Yellow Card scheme - Investigated by CfI and immunisation experts
worldwide
17Pertussis notifications
18Disease incidence
- Main sources of data
- - Statutory notification
- - Laboratory reporting
- Death notification
- Other sources
- - Hospital episodes
- - Sentinel physician reporting
- - Paediatric surveillance
19Serological surveillance
- Residual blood samples from routine tests are
used to provide information on disease immunity
in population - Collected on an annual basis for all age groups
and sent to HPA seroepidemiology unit - Anonymous age and sex known only
- Serological surveys provide information on how
well-protected population is against preventable
disease this needs to be known when deciding on
new vaccine programmes or the need for campaigns
20Rubella susceptibility, 1991
25
Males
20
Females
15
susceptible
10
5
0
0
5
10
15
20
25
30
35
40
Age
21Vaccination CoverageCOVER (Cover of Vaccination
Evaluated Rapidly)
- It is important to know what proportion of any
targeted population has received each vaccine - Since 1988 computerised child health registers
across the country have held vaccination details
for all children resident in the area - Every 3 months, information collected by CfI from
each child health computer as to number of
children who have completed scheduled vaccine
courses at 1,2 5y of age - This information used to evaluate and improve
immunisation coverage by regular feedback to
local areas
22COVER (cont)
- Additionally, COVER data can be used to
- detect change rapidly and monitor trends in
uptake - provide information on impact of media stories
- look for pockets of poor coverage
- estimate vaccine efficacy
- measure impact and success of a vaccination
campaign - It is thus vital than anyone who gives an
immunisation, records and reports that
immunisation to the childs local Child Health
Computer
23Issues in vaccine policy decisions
- As well as information about disease incidence,
vaccine safety and efficacy from surveillance,
vaccine policy makers need to consider - Aim of programme
- Cost of programme
- Population accessibility
- Cultural attitudes and practices
- Facilities available for delivery
24Aim of immunisation programme
- Need to decide overall aim
- To protect those at highest risk
- (selective immunisation strategy)
- or
- To eradicate, eliminate or contain disease
- (mass immunisation strategy)
25Selective vaccination
- Vaccine does not need to be given to all, only to
those at increased risk of disease - Travel
- e.g. Japanese B encephalitis
- Occupational risk
- e.g. Anthrax
- High risk groups
- e.g. Hepatitis B vaccine for neonates,
- Outbreak control
- e.g. Hepatitis A vaccine
26Mass vaccination
- Either
- EradicationDisease and its causal agent have
been removed worldwide e.g. smallpox - Elimination
- Disease has disappeared from one WHO Region but
remains elsewhere e.g. polio - Containment
- The point at which the disease no longer
constitutes a "significant public health problem
e.g. Hib
27Mathematical modelling and cost effectiveness
- Used to predict impact of a vaccination programme
and thus inform policy by - Modelling whether a programme can achieve its
goals - Comparing the costs and impact of various
programme options
28UK mechanisms for making and implementing of
vaccination policy
- Recommendations for vaccine policy
- Joint Committee on Vaccination and Immunisation
- Vaccine policy decisions
- Department of Health
- Licensing of vaccine
- Medicines and Healthcare products Regulatory
Agency (MHRA) - Purchase of vaccine
- Dept Health from pharmaceutical companies
- Control of vaccine (including batch release)
- National Institute for Biological Standards and
Control
29Joint Committee of Vaccination and Immunisation
(JCVI)
- The JCVI is an independent expert advisory
committee. - Its role is
- To advise the Secretaries of State for Health,
Scotland, Wales and Northern Ireland on matters
relating to communicable diseases, preventable
and potentially preventable through immunisation
- Taken from JCVI websitehttp//www.advisorybodi
es.doh.gov.uk/jcvi/) - They review all available evidence and make
recommendations to the Dept Health - who then decide on and make UK vaccine policy
30UK Vaccine Policy published in
- Immunisation against Infectious Disease
- (the Green Book)
- Currently available on Dept Health website
- Chapters can be individually downloaded from the
website and printed off - updated chapters will
replace previous versions as they become
available - Chief Medical Officer Updates, Letters,
Publications and Urgent Communications - These detail any changes to vaccine policy and
recommendations
31Vaccination schedule in UK May 2006
- Primary immunisation
- 2, 3 and 4 months
- Diphtheria-tetanus-acellular pertussis,
- inactivated polio vaccine
- Haemophilus influenzae type b DTaP-Hib-IPV
- Meningococcal group C conjugate MenC
- 12-15 months
- Measles-mumps-rubella MMR
Booster immunisation 3½-5 years Diphtheria-tetanus
-acellular pertussis Inactivated polio
vaccine DTaP-IPV or dTaP/IPV Measles-mumps-rubel
la MMR 15 years Tetanus-low dose
diphtheria Inactivated polio vaccine Td-IPV
32Changes to Childhood Schedule Sept. 2006
- PCV pneumococcal conjugate vaccine (7 valent)
at 2 and 4 months boost at 13 m with MMR - Men C at 3 4 months boost at 12 m with Hib
- BCG school programme stopped for targeted
neonatal immunisation family history and
country of origin - MMR 2 doses under age 25y
33Conjugate pneumococcal vaccines
- Streptoccoccus pneumoniae
- 90 plus different serotypes
- carried in upper respiratory tract
- Wide range of disease
- Conjugate vaccines contain between 7 and 11
serotypes responsible for disease in children - 80 of childhood pneumococcal disease caused by 7
serotypes - Induce long-term memory
- Reduce carriage
- Induce herd immunity
34Place of conjugate pneumococcal vaccine in UK?
- Cost effectiveness data needed to justify routine
use in UK infants - Lower rate of invasive disease in UK vs US
- Role of herd immunity and serotype replacement
may be crucial - Appropriateness for UK schedule
- 3 doses plus booster?
- Acceptability of 3rd injections
- What combinations (MenC/PCV) or alone?
35Varicella Vaccine
- Live attenuated vaccine licensed July 2002 in UK
- Widely used in Japan and US (with MMR)
- Routine vaccination will have an impact on burden
from both - Varicella
- Zoster
- Cost effectiveness analysis and modelling needed
36Chickenpox - epidemiology
Photograph by kind permission of Dr Philip Welsby
and Dr Mike Jones, Edinburgh
Photograph by kind permission of Dr S Ruffle
Twyford
37Annual burden of diseasevaricella zoster
Sources Edmunds et al. Vaccine (2001) Brisson
Edmunds Arch Dis Child (2003)
38Arguments for mass varicella vaccination
- In favour
- Preventable deaths and hospitalisations
- Large economic cost, particularly through
parental work-loss - Against
- Increase in average age at infection could lead
to more severe disease (particularly if low
coverage) - Decrease in incidence of varicella could lead to
an increase in the incidence of zoster due to the
loss of exogenous boosting
39Effect of varicella vaccination on zoster
40Summary
- Infant varicella vaccination highly unlikely to
be cost-effective - Adolescent vaccination may be cost-effective in
UK - Adult vaccination against zoster may also be
cost-effective - No other economic analysis has looked at effect
on zoster - Most have not taken account of herd effects
41New vaccines for UK children?Vaccines where
development is problematic
- Group B meningococcal vaccines
- Concerns about tolerance and safety have limited
development of conjugates - Problems of non capsular (group B) meningococcal
vaccines - Efficacy in the age group at greatest risk
- Coverage of protection against extremely diverse
organism - Feasibility of large enough conducting efficacy
studies
42Confirmed meningococcal infections1998-2003
43Main approach to meningococcal group B vaccine
- Outer membrane vesicles of epidemic strains
- Moderate efficacy in Norway, Cuba, South America
- Limited duration of protection
- Only useful in older age groups
- How much group B disease will be covered?
- Will there be any heterotypic protection
- Will it cover variants of same Por A
- May be useful in response to an epidemic of a
single clone - Currently being conducted in New Zealand
44New vaccines for UK children?Possible
- Influenza is major cause of morbidity and
mortality in developed world - Elderly account for the vast majority of deaths
- Hospital admissions common in other age groups
- US have now recognised the need to vaccinate
children under two - Current influenza vaccine
- Need for annual vaccination
- Possible role of live attenuated vaccines in the
future? - Children are major source of infection for others
45Hospitalisation rates for influenzaUSA studies
/100,000
- Children
- Under one 496-1038
- Aged 1-2 yrs 186
- Aged 3-4 yrs 86
- Aged 5-14 yrs 41
- Adults
- Aged 15-44 yrs 23-25
- Aged 45-64 yrs 13-23
- Aged gt 65 yrs 125-228
- What is the burden of influenza in children in
the UK?
May already have been reduced by between 30-70
by vaccination
46Live attenuated influenza vaccine
- Live attenuated, cold-adapted viruses
- Replicate in upper but not in lower airways
- Protective mucosal immunity without disease
- Trivalent preparation given by nasal spray
- same strains as killed vaccine (A H3N2, A H1N1,
B) - LAIV is an now recommended in the US
- an alternate to inactivated vaccine for healthy
people aged 5-49 years - Not for those at high risk, or with asthma
47Recommendations in the US
- Inactivated vaccine is strongly recommended for
- All age groups at risk
- Healthy adults aged over 65 yrs
- Adults aged 50-64 yrs (high prevalence of RFs)
- Inactivated vaccine is encouraged (where
feasible) - Healthy children aged 6-23 months
- Moving towards a policy of annual vaccination
for all aged 6-23 months within three years - Also recommending use of LAIV for older healthy
children - Role of influenza vaccines for the UK unclear
48Summary
- Several likely developments in the UK schedule
- Introduction will depend upon good surveillance
data and economic and epidemiological analysis - Practical issues must not be under-estimated
- number of injections
- complexity of schedules
- Safety issues have the ability to side-track
programme - Important that justification for the introduction
of vaccines are clear