Lecture 11. Public Health 2: What are the Current Immunisation Policies in the UK and Why? Flashcards
What is JCVi and what is there role?
Joint Committee on Vaccination and Immunisation
Advises Department of Health (comes under NICE umbrella)
Has a statutory right that if the health minister want a recommendation from the JCVI, they have to follow the JCVI’s advice
What is the Green Book?
Has information about every vaccine
Every GP has one and it is updated very so often
What does the Green Book contain?
Schedule for routine immunisation
Why is there a pressure to amalgamate vaccines with similar due dates together?
Parents don’t want to keep bringing their children to the GP -want to get every vaccine done at once (some can’t be given together as efficacy is reduced)
Why are most of the vaccines given to the very young?
Because you want to protect them for as long as possible (most of these vaccines will last their lifetime)
When is the measles, mumps and rubella (MMR) vaccine given, and when is the booster given?
Initial injection - One year old (on or just after birthday)
Booster - Three years four months old or sooner
What are the five aims of public health interventions?
Control
Elimination of Disease
Elimination of Infection
Eradication
Extinction
What is the aim of control?
Reduction of disease incidence, prevalence, morbidity or mortality to a locally acceptable level as a result of deliberate efforts. Continued intervention measures are required to maintain the reduction
What is the aim of elimination of disease?
Reduction to zero of the incidence of a specified disease in a defined geographical area as a result of deliberate efforts. Continued intervention measures are required
What is the aim of elimination of infection?
Reduction to zero of the incidence of infection caused by a specified agent in a defined geographical area as a result of deliberate efforts. Continued measures to prevent re-establishment of transmission are required
Some diseases have infection eliminated before disease
What is the aim of eradication?
Permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts. Intervention methods are no longer needed
What is the aim of extinction?
The specific infectious agent no longer exists in nature or the laboratory
What is an example of a disease that was controlled?
Haemophilus influenzae B (HiB), booster introduced in 2006 after honeymoon phase wore off
How diphtheria eliminated locally (not worldwide)?
Introduction of immunisation in 1940 eliminated the pathogen - massive reduction in both infections and deaths
Why does the number of measles cases per year zigzag?
Measles outbreak alternate between small and large outbreaks (one year small outbreak, next year big outbreak)
Because the R₀ of measles is so high, what percentage of the population would need to be vaccinated to ensure herd immunity?
~97%
Why was there a measles outbreak in Swansea in 2012?
A local newspaper was publishing anti-vaxx messages
What vaccine led to a huge drop in Polio cases in 1962?
Sabin
Since 2004, why did doctors switch from OPV (live attuned oral polio vaccine) to IPV (inactivated polio vaccine)?
IPV has a lower risk than OPV
Get away with less effectiveness as polio is less prevalent within the population
When was the WHO European Region (EUR) deemed free of indigenous poliovirus transmission?
21 June 2002
What were the first two WHO regions deemed polio free?
Region of the Americas - 1994
Westen Pacific Region - 2000
How many estimated people live in countries and territories that are certified free of endemic wild poliovirus transmission?
3.4 billion
What three countries have not stopped polio transmissions?
Pakistan
Afghanistan
Nigeria
How many reported cases of poliovirus were there in 2017?
22
When did the smallpox eradication campaign take place?
1967-77
When did the dracunculiasis (Guinea worm) eradication campaign take place?
1980 - should also result in extinction (dogs identified are reservoir hosts)
What are the main problems with vaccines?
Immunogenicity
Reactogenicity (side effects of vaccine)
Coverage - proportion of the population immunised & protected
What is Hepatitis B (HBV)?
Childhood disease in most developing countries – Mass immunisation as soon as possible after birth
Adult, risk behaviour associated infection in most developed countries - Mass immunisation vs. Targeted immunisation of identified risk groups
This is a question with health-economics can have a substantive input
What’s more expensive, mass immunisation or targeted immunisation?
Targeted
What does HBV result in death?
HBV causes deaths chronic infection leading to liver disease, which develops over years
What are the pros and cons of mass immunisation?
Mass immunisation is very effective, but there is a delay of 15yrs until the effect is seen (because of start of risk behaviours)
Mass immunisation results in 1 carrier prevented per 200 doses
What are the pros and cons of targeted immunisation?
More effective immediately than mass immunisation, but overtaken at about 25 years before effect seen
Targeted immunisation is much more cost-effective (carries prevented per dose of vaccine given)
What is the current incidence of HBV?
Very low (~500 per year), but not zero
Why hasn’t HBV been eradicated?
Too costly to eradicate the last places
What countries are resisting the global momentum to vaccinate everybody and why?
UK, The Netherlands and Scandinavian countries
This will be a barrier to eradication since individuals start risk behaviours before they are immunised
Economics of immunisation mean that a mass programme in UK is expensive and not cost-effective
What caused the additional complications of HBV eradication?
Caused by age-related risks of becoming a carrier
What HPV and what are the symptoms?
Human papilloma virus
Genital warts and cervical cancer (cervical cancer is the biggest effect and the most costly)
Sexually transmitted
Which disease causes a bigger burden on the NHS, HBV or HPV?
HPV
What are the population consequences of vaccination?
Immunisation reduces the number of susceptibles
Makes infection rarer - those not vaccinated will be infected later in life: possibly with more disease which makes vaccine relatively more more dangerous
Changes the dynamics
Older population more at risk
What caused the sharp rise in pertussis cases in 2011?
Children were too young to immunise, therefore mass emergency vaccines were given to mothers in the last trimester so maternal antibodies could give the babies immunity
