Ebola vaccines, malaria vaccines and
certain travel-related vaccines
Lynne Webber
Consultant pathologist and clinical
virologist
The History of Medicine
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2000 BC: Here take this root and eat it!
1800 AD: Try this snake oil
1900 AD: That snake oil is heathen, say a prayer
1920 AD: That prayer is useless, try this lotion
1940 AD: Stop that lotion, here swallow this pill
1980 AD: Stop swallowing that pill, here use these
antibiotics
• 2000 AD: The antibiotics don’t work anymore.
Here take this root and eat it!
Laboratory safety:
Laboratory biosafety level criteria
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It’s a Friday afternoon, about 15h30 and you are
starting to look forward to the weekend when
one of your staff brings a sample to you. In the
diagnosis field it says “?VHF”.
The sample is not packaged in any special way
and there are no details of the doctor who sent
the sample.
If you have not prepared for such an event, you
are not going to have a weekend you will have a
nightmare.
Differential Diagnosis
Septicaemia
 Infections such as: malaria, typhoid, Tickbite fever.
 Viral infections – various
 Non-infective: neoplasia, drug sensitivity,
OD, snake bite, poisoning, tribal medicines
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Containment levels for biocontainment
laboratories
BSL-4
BSL-3
BSL-2
BSL-1
BSL = biosafety level
RISK
GROUP
BSL
LAB TYPE
LAB PRACTICES
SAFETY
EQUIPMENT
1
Basic –
Biosafety
level 1
Basic teaching
Research
GMT
None: Open bench
work
2
Basic –
Biosafety
level 2
Primary health
services
Diagnostic
services
Research
GMT + protective
clothing
Biohazard sign
Open bench + BSC
for potential aerosols
3
Containment
– Biosafety
level 3
Special diagnostic As level 2 + special BSC and/or other
services
clothing, controlled primary devices for
access, directional ALL activities
research
airflow
4
Maximum
containment
– Biosafety
level 4
Dangerous
pathogen units
As level 3 + airlock
entry, shower exit,
special waste
disposal
Class III BSC or
positive pressure suits
in conjunction with
Class II BSCs, double
autoclave (through
wall), filtered air
BSC=biological safety cabinet; GMT=good microbiological techniques
Biosafety level 1 (BSL-1)
• Well characterized agents
– Not known to consistently cause disease in
healthy adult humans
– Minimal potential hazard to lab personnel & the
environment
• Appropriate for
– Undergraduate and secondary educational
training and teaching labs
BSL-2
• Procedures
likely to produce
aerosols are
performed in a
BSC
• Doors kept
closed
• Hazard signs
• Potentially
contaminated
wastes
separated from
the general
waste system
Biosafety level 2 (BSL-2)
Biosafety level 3 (BSL-3)
• Indigenous or exotic agents with a potential for respiratory
transmission
• May cause serious and potentially lethal infection
• Primary hazards to personnel relate to autoinoculation,
ingestion and exposure to infectious aerosols
• More emphasis on primary and secondary barriers e.g.
– All manipulations should be performed in a BSC or other enclosed
equipment
– Secondary barriers for this level include
• Controlled access to the lab
• Specialized ventilation requirements that minimize the release of
infectious aerosols from the laboratory
Arbo- & certain other viruses assigned to
BSL-3 (CDC)
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Aino
Akabane
Banna
Bhanja
Central Eurupe TBE
Chikungunya*
Cocal
Dhori
Dobrava-Belgrade
Dugbe
Everglades
Flexal
Germiston
Getah
Hantaan
Israel Turkey meningitis
Japanese encephalitis*
Junin
Kairi
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Kimberley
Koutango
Louping ill*
Mayaro
Middelburg
Mobala
Mopeia
Mucambo
Murray Valley encephalitis
Nairobi sheep disease
Ndumu
Negishi
Oropouche
Orungo
Peaton
Piry*
Powassa
Puumala
Rift Valley fever*
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Rocio
Sagiyama
Sal Vieja
San Perlita
Semliki Forest
Seoul
Sin Nombre
Spondweni
St. Louis encephalitis
Thogoto
Turuna
Venezuelan equine
encephalitis*
Vesicular stomatitis
Wesselsbron*
West Nile*
Yellow fever*
Zinga
Biosafety level 3 (BSL-3)
• All infectious material handled in
BSCs
– Located away from doors, from
room supply louvers, and from
heavily-traveled lab areas
• PPE e.g. solid-front or wraparound gowns, scrub suits or
coveralls are worn by workers
when in the lab
– Not worn outside the lab
– Reusable clothing is
decontaminated before being
laundered
– Clothing is changed when overtly
contaminated
Biosafety level 3 (BSL-3)
• Laboratory Facilities (Secondary
Barriers)
– Lab separated from areas that are open
to unrestricted traffic flow within the
building
– Access to the lab is restricted
– Passage through a series of two selfclosing doors is the basic requirement
for entry into the laboratory from access
corridors
Biosafety level 3 (BSL-3)
• A ducted exhaust air ventilation system which creates directional
airflow which draws air into the laboratory from "clean" areas and
toward "contaminated" areas
– Exhaust air is not
recirculated to any
other area of the
building
– Outside exhaust
must be dispersed
away from
occupied areas and
air intakes or the
exhaust must be
HEPA-filtered
Biosafety level 3 (BSL-3)
Biosafety level 4 (BSL-4)
• Applicable for work with dangerous & exotic agents
– High individual risk of life-threatening disease
– May be transmitted via the aerosol route
– No available vaccine or therapy
• E.g. Marburg or Crim-Congo haemorrhagic fever
• The primary hazards to personnel are
– Respiratory exposure to infectious aerosols
– Mucous membrane or broken skin exposure to infectious
droplets
– Autoinoculation
Arbo-, Arena- & Filoviruses
Assigned to BSL- 4 (CDC)
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Crimean-Congo haemorrhagic fever
Ebola & Marburg viruses
Tick-borne encephalitis viruses
Omsk haemorrhagic fever
Russian Spring-Summer encephalitis
Guanarito, Machupo, Junin & Sabia viruses
Kyasanur Forest disease
Lassa
Biosafety level 4 (BSL-4)
• The lab worker's complete
isolation from aerosolized
infectious materials is
accomplished primarily by working
in
– Class III BSC (Cabinet laboratory)
or
– Full-body, air-supplied positivepressure personnel suit (Suit
laboratory)
• BSL-4 labs may be based on either model
or a combination of both models in the
same facility
Biosafety level 4 (BSL-4)
• Personnel wears one-piece positive pressure
suit that is ventilated by a life-support system
protected by HEPA filtration
Biosafety level 4 (BSL-4)
• Appropriate communication
systems are provided between
the lab and the outside
– e.g. voice, fax, computer
Biosafety level 4 (BSL-4)
Are There New Threats With
New Species of Ebola virus?
• A US physician working in Bundibugyo
district remembers the day that her
Ugandan colleague, Jonah Kule, went to
investigate rumours of a mysterious
epidemic in Kikyo
– “We had not heard of any bleeding, just
vomiting and diarrhoea…we wondered if it was
a cholera outbreak…When he came back he
guessed typhoid fever, due to the prominent
abdominal pain.”
– Kule died of Ebola on 4th December 20007
• A recent Ebola outbreak occurred in
Bundibugyo, Uganda from August 2007 –
January 2008
Ebola Virus
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Order: Mononegavirales
Family: Filoviridae
Genus: Ebola virus
Species: Zaire ebolavirus (ZEBOV)
Sudan ebolavirus (SEBOV)
Ivory Coast ebolavirus (ICEBOV)
Reston ebolavirus (REBOV)
?? Uganda ebolavirus
Bundibugyov
New Ebola virus species
Ebola Virus
• Single stranded
negative sense
RNA genome in a
helical
nucleocapsid
Ebola outbreak - online
• “Ebola vaccine trials in Africa and Europe”
• “rVSV Ebola vaccine (recombinant vesicular
stomatis virus induced Ebola – specific
immune responses)
• “Chimpanzee adenovirus Ebola vaccine –
preliminary report” (Ebola glycoproteins)
• “panic, paranoia and public health”
• “Ebola vaccine – an urgent international
priority”
Ebola vaccines under development
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cAd – EBO Z
VSV – EBOV
Advac/MVA – BN
EBOV-GP
Nasal vaccine – still in monkey trials
Vaxart tablet – temperature stable tablet
Novel recombinant adenovirus type-5 vectorbased Ebola vaccine
• Whole virus vaccine – EBOV – delta – VP30
CCTV monitoring of inside & perimeter of BSL3
‘In Heaven you won’t hear the
mosquito”
Finnish proverb
Malaria vaccine
• Considerations:
• Parasite diversity
• Address the symptom or the source such as
anti-parasitic immunity and anti-toxic
immunity potential targets include the
parasitic stage and the actual target – malaria
life cycle
• Mix of antigenic components
• Vaccine delivery system
Protozoan parasites of genus
Plasmodium
• P.falciparum – responsible for the majority of
malaria deaths and is the most prevalent sp in
sub-Saharan Africa
• P.vivax – second most significant species,
prevalent in South-East Asia and Latin America;
• P.ovale – dormant liver stage complication, leads
to clinical symptoms;
• P. malariae– small percentage of infections;
• P.knowlesi – infects primates, can cause human
malaria, mode of transmission unclear
Parasite diversity
• P.falciparum - evolutionary changes, drugresistance
• P.falciparum has a very high rate of replication
Symptom or the source
– antibody response and cell-mediated (T-cell)
immune responses
• Antiparasitic immunity – antibody response
and a cell-mediated (T-cell) immune response
• Anti-toxic immunity – suppression of the
immune response factors or anti-toxic byproducts production. Example tumour
necrosis factor could reduce severe malaria
symptoms (therapeutic vaccines!)
Potential vaccine targets
• Sporozoite – hepatocyte invasion, direct antisporozite
• Hepatozoite – direct anti-hepatozoite
• Asexual erythrocyte – anti-host erythrocyte,
blocking antibodies, anti-soluble toxin
• Gametocytes – anti-gametocyte, egress
blocking antibodies
• Ad infinitum
Vaccine delivery systems
• May require delivery to different areas and by
different means
• Adjuvants – hepatitis B virus in the RTS,S
vaccine, key components, high doses may
elicit an auto-immune response
• Two vaccines – one generating a blood
response, the other a liver-stage response
RTS,S vaccine/Mosquirix
• Most recently developed recombinant vaccine
• It consists of the P.falciparum
circumsporozoite protein (CSP antigen/protein
from the pre-erythrocytic stage)
• HBV plus a chemical adjuvant boosts the
immune response by inducing high antibodies
that block the parasite from entering the liver
• 24 July 2014 EMA recommended to vaccinate
children aged 6 weeks to 17 months
2015 WHO policy
Mosquirix for national immunisation
programmes in sub-Saharan Africa
Yellow fever
Zambia – yellow fever vaccine
zone
Rift Valley Fever
Countries with endemic disease
and substantial outbreaks of
RVF:
Gambia, Senegal, Mauritania, Namibia, South Africa, Mozambique,
Zimbabwe, Zambia, Kenya, Sudan, Egypt, Madagascar, Saudi Arabia, Yemen
Countries known to have some
Botswana, Angola, Democratic Republic of the Congo, Congo, Gabon,
cases, periodic isolation of virus, Cameroon, Nigeria, Central African Republic, Chad, Niger, Burkina Faso, Mali,
or serologic evidence of RVF:
Guinea, Tanzania, Malawi, Uganda, Ethiopia, Somalia
Viruses borne by mosquitoes
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Many and many
Relevant for Africa:
West Nile virus
Yellow Fever
Rift Valley Fever
Sindbis
Wesselsbron
Middelburg
Chikungunya
Bunyaviruses: Shuni virus
• Ortobunyavirus identified in brain of
fatal neurological case in horse 2009
• Subsequent screening of 104
neurological diseased horses ;
identified Shuni virus in 6%
• Two
unpublished
reportsof
ofNeurologic
Shunivirus Disease in Horses
Shuni
Virus as Cause
in horses with neurological disease, 1
from
Zimbabwe
andJune
1 from
SA in 1970’s
Charmaine
van Eeden,
H. Williams,
Truuske G.H. Gerdes, Erna van Wilpe,
• ?Adrianne
Importance
inRobert
SA Swanepoel and Marietjie Venter
Viljoen,
SAE 48 10
78
SAE 72 09
90
SAE 38 10
Shunivirus
SAE 39 10
95
SAE 27 10
82
SAE 18 09
Shuni Virus
91
100
Aino Virus
Kaikalur Virus
Sango Virus
Peaton Virus
100
Tinaroo Virus
84
Akabane Virus
82
Yaba-7 Virus
Sabo Virus
100
Shamonda Virus
100
Sathuperi Virus
Douglas Virus
Simbu Virus
Facey’s Paddock Virus
Buttonwillow
Virus
98
Mermet Virus
Ingwavuma Virus
0.08
Figure 3: Phylogenetic analysis of the s-segment of Shuniviruses, are compared to
other members of the Simbu virus serogroup, ortobunyavirus genus, family
bunyaviridae. Viruses detected in in horses with neurological symptoms in
South Africa are indicated by the prefix SAE.
West Nile virus (WNV)
• WNV a mosquito-borne member of the Flaviviridae family
(Flavivirus)
• Belongs to the JE-serogroup, includes JEV (Asia), Kunjin and
MVE (Australia)
• Isolated in 1937 from the blood of a 37y.o
febrile woman participating in a malaria
study in the West Nile district of Northern
Uganda
Transmission
• Maintains enzootic life cycle between viremic birds and
mosquitoes (primarly Culex species)
• Commonly infects humans and horses (dead end hosts)
• Large host range
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225 spp birds
29 spp mammals
49 spp ticks/mosquitoes
Limited transmission
• Survives winter in
hibernating females
Distribution
2002
Short- and long-term outcomes
WN Fever
Younger individuals
Few physical/neurological sequelae
Older individuals high mortality
Exacerbation of underlying conditions
Extreme fatigue is common  lasting
up to 36 days post-illness
Self-assessed somatic complaints –
Fatigue, weakness, concentration problems
Prevention
Active arboviral surveillance &
mosquito vector control in affected areas
Mapping of breeding sites
Surveillance and vector control implemented
early to disrupt springtime viral activity
Chemical spraying to control adult vectors as
emergency measure after detecting WN activity
Public outreach
Avoid or decrease risk of mosquito bite- repellent
Avoid areas where mosquitoes are common
Limit outdoor activity in peak biting periods
Vaccines
Inactivated vaccines *
Subunit vaccines
Cross-reactive vaccines
DNA vaccines
Live-attenuated vaccines *
Conclusion
• Thank you!
• Touched the tip of the iceberg
• Indian Cherokee saying – don’t let yesterday
use up too much of today