Download Victims of their own success: Vaccines for infectious diseases

Victims of their own success:
Vaccines for infectious diseases in Australia
Frank Bowden
Professor, ANU Medical School
Infectious Diseases Physician, Canberra Hospital
Timeline of vaccine development: 1798 - 1955
Diphtheria
Rabies
1798
Smallpox
1885
1896
Cholera
Pertussis
1924
1923
Tetanus
http://www.nature.com/nrmicro/journal/v9/n12/fig_tab/nrmicro2668_I1.html
1926
Influenza
1927
BCG
1936
1955
Polio
Timeline of vaccine development: 1963 - 2016
1963
Measles
1969
Varicella
Zoster
Hepatitis B
Rubella
1974
1981
Meningococcus
http://www.nature.com/nrmicro/journal/v9/n12/fig_tab/nrmicro2668_I1.html
1987
HiB
1995
Rotavirus
1996
Acellular
pertussis
1999
2006
HPV
1923 in Australia
Annual cases
Rate /100,000
Diphtheria
23,199
425
Measles
148,040
2,741
Aus pop
Communicable Diseases Intelligence Hall,R Vol17/No. 11
5.4M
1930
Aus pop
6.5M
Communicable Diseases Intelligence Hall,R Vol17/No. 11
Annual cases
Rate /100,000
Pertussis
45,000
700
Tetanus
98
1.5
1938
Poliomyelitis
Communicable Diseases Intelligence Hall,R Vol17/No. 11
Annual cases
Rate /100,000
2776
39.1
1961 - The Tied Test
Annual cases
Rate /100,000
12,000
120
Hepatitis A
Communicable Diseases Intelligence Hall,R Vol17/No. 11
Aus pop
10.1M
Bad diseases
Measles
● Diarrhoea
● Otitis media
● Pneumonia
● Encephalitis
●
SSPE
Mortality 1960 ^ 1 in 1000
Pertussis
Mortality 1 in 200 if < 6 months
Rubella
Epidemics of deafness in Australia
1899, 1916, 1924, 1925, and in
1938-41.
Tetanus
2004 Aceh tsunami: 108 deaths
Sydney - 1940
● Rubella epidemic across Australia in 1940
● Following year Gregg describes 78 infants
with unusual cataracts; 68 born to mothers
with rubella in pregnancy
● 1943 adds deafness and congenital heart
disease
● Mental retardation recognised
Norman Gregg 1892-1966
Rubella epidemic of 1962 - 65
● 12.5 million cases of rubella occurred
in the United States
● 2,000 cases of encephalitis
● 11,250 fetal deaths
● 2,100 neonatal deaths
● 20,000 infants born with congenital
rubella syndrome
Zika virus
● 3358 Zika cases in the US*
● <100 in returning Australians
*21 September 2016
Aedes egypti
Vaccination
Parental Warning:
Some viewers may the find the
following slides offensive
It contains arithmetic
Reproductive number : R0
“The number of new cases that an
infected individual causes in a
totally susceptible population.”
R0 < 1
:
no epidemic
R0= 1
endemic disease
R0 > 1
epidemic disease
Endemic disease
R0 = 1
Epidemic disease
R0 = 3
Herd immunity
Herd immunity
The threshold proportion of people required to be
vaccinated to achieve a decline in incidence of
infection
Herd immunity threshold (HIT) = 1 - 1 / R0
Herd immunity thresholds
R0
Herd immunity threshold
Ebola
2
50%
Influenza
2.5
60%
Smallpox
6
83%
Measles
15
93%
Unconditional surrender
The end of Smallpox - 1980
Ali Maow Maalin
Frank Fenner
The end of Polio - ? 2020
Victory
Measles in the UK
Source: Public Health England
National Notifiable Diseases System
● Globally WHO estimates 17M lives
saved between 2000 and 2016 due
to measles vaccination
● But still 114,000 deaths annually
Rubella
National Notifiable Diseases System
Haemophilus influenzae Type B (HiB)
National Notifiable Diseases System
Meningococcal disease
Varicella ?
Susceptible
Infected
Recovered
The Cancer Vaccines
Hepatitis B
● 10-15% chronic infection in
Asia (120 million in China)
● 600,000 deaths annually
Human papillomavirus
274,00 deaths
274,000* deaths from cervical
cancer annually 85% in the developing world
*World Health Organisation
Modest successes (or worse…)
Pneumococcus
Influenza
Pertussis
Complete failures
No vaccines for:
HIV
Hepatitis C
Malaria
(TB)
Dengue
RSV
Ebola
Chlamydia
Gonorrhoea
Trichomonas
HSV 1 and 2
Chikungunya
Zika
Staph aureus
E.coli
Victims of their own success
Risk versus benefit
Rotavirus vaccine
1998 1st vaccine withdrawn after 1 in 12,000
risk of intussusception observed
Between 1998 and 2006 WHO estimated 4.2
million deaths from rotavirus
200 cases of intussusception in Australia
annually
14 additional cases per year due to vaccine
Annual Australian incidence pre-2007
22,000 ED presentation
10,000 admissions
60-70% reduction post-2007
The Cutter Incident
● 200,000 injected with live poliovirus
● 70,000 infected
● 200 paralysed
● 10 died
Melbourne suburbs (red) with less than 90% vaccine coverage
Timeline of vaccine development: 1963 - 2016
1963
Measles
1969
Varicella
Zoster
Hepatitis B
Rubella
1974
1981
Meningococcus
http://www.nature.com/nrmicro/journal/v9/n12/fig_tab/nrmicro2668_I1.html
1987
HiB
1995
Rotavirus
1996
Acellular
pertussis
1999
2006
HPV
Summary
Vaccines are the most effective biomedical
interventions in history
Eradication of 1 (nearly 2) diseases, elimination
of many others
As the diseases they protect against disappear,
the benefit of vaccines become less clear to the
potential recipient
Modern parents will not just follow the advice of
health authorities
A nuanced, respectful conversation is necessary