guanarito buruli crimean-congo dengue tb · hookworm vaccine: human trials. human hookworm vaccine...
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Tropical Disease Vaccines
HIV Malaria
TB
Schistosomiasis
Leischmaniasis
Ascariasis
Hookworm
Dengue
Trachoma ChagasLeprosy
Buruli
Trypanosomiasis
Yellow Fever
Ebola
Marburg
Lassa
Crimean-Congo
Rift Valley Fever
Junin
Machupo
Hantaan
Guanarito
Ebola
Neglected Tropical Diseases
1in 6have a
disease you have never heard of…
Neglected Tropical Diseases
Disease and Poverty linked
NTDs = Poverty Promoting
60% of Global Disability linked to Infectious Diseases
No Market for drugs
Neglected Tropical Diseases
13 Poverty Promoting Illnesses
3 Protozoans- Leishmanisis- Trypanosomiasis- Chagas
3 Bacterial-Trachoma- Leprosy- Buruli Ulcer
7 Helminths- Schistosomiasis- Hookworm- Ascariasis
Schistosomiasis
Viral Hemorrhagic FeversNBC News
Background: Viral Hemorrhagic Fevers
FeverMyalgiaHeadacheProstrationHemorrhageCapillary leak
Background: Viral Hemorrhagic Fevers
Filoviridae: Flaviviridae
Ebola HF – Ebola Virus Mosquito-borneMarburg HF – Marburg Virus - Yellow Fever
- Dengue HF – Den 1,2,3,4Tick-borne- Kyasanur Forest Disease- Omsk HFBunyaviridae
- - Hataan- Puumala- Sin Nombre (4 Corners)
Distribution: Yellow Fever Virus
Distinctly lacking in Asia
Flavivirus: Located in Africa and the Americas
Origins: W. Africa Americas
Vector: Aedes aegypti spp.
Transmission: Eggs dessicate and travel across borders
Types: Sylvan (jungle) and Urban (outbreaks)
WHO data
10% of Philadelphia perished
Background: Yellow Fever Virus
1878: New Orleans - 20,000 deaths
“The American Plague”
Background: Yellow Fever Virus
1898: Spanish American War- 989 War related fatalities
- > 5000 deaths to disease
- Walter Reed put in charge of Yellow Fever Commission
Walter Reed
Disease: Yellow Fever Virus
Classic Yellow Fever – 3 periods
Infection: Fever, headache, Faget’s Sign, black emesis (Day 3), nausea, bleeding
Remission: Symptom resolution - Hours to days
Intoxication: Fever, epigastric tenderness, bleeding, hypotension, death
Councilman body in liver
Treatment and Prevention: Yellow Fever Virus
No specific treatment exists. Mortality: 5-50% depending on severity of illness. 200,000 cases with 30,000 deaths.
Vaccine- Live attenuated1951 Nobel Prize - Max Thieler
www.rayur.com
RNA enveloped virus
Vaccine: Yellow Fever Virus
Yellow Fever Vaccine – Based on 17D strain and administered since the 1930’s
Safety Profile – 600 million doses administered: 12 post-vaccination VF cases identified
Contraindications – Egg allergy, < 6 mo or > 59 years, thymus disorders, primary immunodeficiences or on immunodeficiency drugs.
Yellow Book – Rare cases of Neurotropic or Viscerotropic disease in travelers (8 died – 1.2-2.2 per 100,000)
2013 – WHO concluded that lifelong immunity results after 1 dose
Background: Dengue Virus
Most important arboviral infection: 4 distinct dengue virus serotypes (DENV-1-4)
Antigenically distinct with no cross-reactivity (single-stranded RNA virus)
Transmitted: Aedes aegyptii
DENV-2 is most distinct with little homology 1, 3, 4
Pathology: Disseminates to RE system and into blood. Endothelial swelling and perivascular edema, extravasation of blood
Incubation: 3-14 days
390 million cases/year(95% CI 284-588)
500,000 severe cases/year
1970 – 9 countries
2015- 110 countries
Disease: Dengue Virus Symptoms
Rash: 1. Transient flush, mottling, fleeting pinpoint eruption
2. Maculopapular/scarlatiniform (d 3-4), pruritic
3. Convalescent rash: Confluent petechial rash with scattered pale rounded areas of normal skin
20 petichiae/inch2 after tourniquet deflated (5 min)
Disease: Dengue Hemorrhagic Fever
Dengue Shock Syndrome (WHO)
- Fever or history of fever 2-7 days- Any hemorrhagic manifestation - Thrombocytopenia (platelet count of
<100,000/mm3) - Increased vascular permeability
Can develop Dengue to each strain (up to 4 episodes)
DHF risk increases if you have “seen” a previous strain (ADE)
Dengue Virus: Antibody-dependent Enhanced Immunity
Initial Infection
Invade Cell and replicate
B cell (ab) and T cell immunity develops
After virion release, ab coat and MΦ engulf
Alternate DenV Infection
Memory B cells produce ab
Poor binding to alternate DENV strain
Escape MΦ and replicate
Vaccine Development: Tetravalent Dengue Virus
Live attenuated
Inactivated
Sub-Unit
Viral-like particles and DNA
Most advanced in testing – Phase 3Yellow Fever and JE models workSanofi Pasteur**, NIAID, WRAIR
More expensive to manufactureNo risk of transmission to mosquitoesCan use in immunocompromised WRAIR/GSK – TDEN-PIV
Phase 1 testing
Pre-clinical and Phase 1
Vaccine Development: Dengue Virus
Sanofi-Pasteur (CYD-TDV) tetravalent chimeric vaccine
Efficacy –
Dengue ~60%
Phase III VE Asia S. America1- 50% 50.3%2- 35% 42.3%3- 78.4% 74.0%4- 75.3% 77.7%
http://cvi.asm.org/content/16/12/1709/F3.large.jpgCapeding, Lancet, 2014, 384: 1358
Vaccine Development: Sanofi Chimeric Vaccine
Phase 3 - > 35,000 Children aged 2-16 years, 10 countries
Year 3 – Children under 5 had 5X risk of dengue hospitalization (0.99 vaccinated vs 0.2% controls = 20 kids (5 with DHF) vs. 2 kids)
By Year 3 – VE in children < 9 yr was 44.6% (95% CI 31.6%-55.0) whereas >9 yr was 65.6% (95% CI 60.7-69.9)
Children seronegative at enrollment had strong nAb responses but poor protection compared to seropositive children
Strong evidence of antibody-dependent enhancement Year 3
Ebola
Background: The ebola virus
• Enveloped, host cell membrane with Ebola glycoprotein• Non-segmented, negative sense, ssRNA• 7 genes, 19kb• Family: Filoviridae (filum, Latin, thread)• Genus: Ebolavirus• Species:
– Zaire (EBOV)– Sudan (SUDV)– Ivory Coast or Tai Forest (TAFV)– Bundibugyo (BDBV)– Reston (RESTV)
• BSL-4, Bio-threat category ACourtesy – James Campbell, MD
Background: Virus Presentation
1967: Marburg, Germany- Imported Ugandan Green Monkeys
- Laboratory workers fall ill
- 7 of 31 die.
- Virus later identified and named Marburg.
- Predilection for children – 75% < 5 years of age
- High case mortality – 89%
- Egyptian Fruit Bat – Rousettus aegyptiacus
Background: Virus Presentation
1976: Yambuku, Congo-“Green Monkey Fever”
-Villagers fall ill – yellow fever?
-Women >> Men
-Ground Zero - Yambuku Mission Hospital – 200 dead
Mission Nuns and a Priest Self Quarantined – 4 colleagues had died
Please stop, anybody who crosses here may die….
Background: Virus Presentation
- Two vials of blood sent to Belgium – 1 broke
- Peter Piot examined
- WHO ordered vials sent to CDC
- Electron microscopy image of virus
- CDC confirmed it was not Marburg
- New virus – Named it Ebola
Background: Virus Presentation
- International team arrived to help quell the outbreak and study the virus
- Yambuku Mission – 5 syringes
- Pre-natal care and deliveries common
- Also associated with funerals
- Outbreak lasted 3 months and ~300 dead (88% mortality)
- Simultaneous outbreak –Sudan 1976
- Disappeared until 1994
The Ebola River
Epidemiology: Transmission
- Bushmeat is a primary protein source in West/Central Africa
- Accounts for ½ of meat at market –20% are primates
- Humans exposed during slaughter
Epidemiology: Transmission
Downstream Effects- 95% mortality in Great
Apes, 77% Chimps
- 1/3 Great Apes Dead
- Desperately require a vaccine as well
Epidemiology: Reservoir
- Primates are not a reservoir
- Bats long suspected
- Marburg – R. aegyptiacus
- Ebola - Little collared and hammerhead fruit bats
- Bats are a delicacy in W. Africa
Marburg and Ebola Vaccine:
GP = Glycoprotein – basis of vaccine
Viral Membrane – May contain HLA or other human surface receptors
VP40 and VP24: Ebola matrix proteins critical for budding
Ebola RNA: Packed with NP protein for nucleocapsid
Ebola Polymerase: Synthesizes positive sense virus RNA
VP35 and VP30: IFN antagonist ebola proteins
Lipid membrane wraps viral particle
Pathogenesis: Virulent Factors
Marburg and Ebola Vaccine:
Viral Pathology:Single-strand RNA virus. Evades type I IFN’s by VP35 blockade of induction and VP24 blockade of IFN action.
Circulating infected monocytes express tissue factor leading to DIC
Endothelial and parenchymal cell infection, likely mediated by glycoprotein results in further tissue damage.
Pathogenesis: Virulent Factors
Outbreak: Ebola Epidemic
December 6, 2013: Guéckédou, Guinea- Child Zero dies – linked to fruit bat
-Confirmed by WHO- March 2014
-Previous to this – only W. African Ebola outbreak seen was in Cote D’Ivoire
-Lassa Fever suspected
Guéckédou
NEJM 10.9.2014
Outbreak: Ebola Epidemic
Ebola deathsFigures up to 26 April 2015
10,899Deaths - probable, confirmed and suspected(Includes one in the US and six in Mali)
4,608 Liberia
3,899 Sierra Leone
3,584 Guinea
8 Nigeria Source: WHO Getty Image
Treatment: Ebola Vaccines
All depend upon a viral platform and ebola genes - 3
C. Ad26-EBOV/MVA EBOV– J&J, Janssen, and Bavarian Nordic - Adenovirus 26-EBOV prime boosted by MVA
NEJM Oct 2014
VRC, UMB, Emory, Oxford UK, Mali
Canada, US, Gabon, Switzerland, Germany
Treatment: Ebola Vaccines
All depend upon a viral platform and ebola genes - 3
C. Ad26-EBOV/MVA EBOV– J&J, Janssen, and Bavarian Nordic - Adenovirus 26-EBOV prime boosted by MVA
NEJM Oct 2014
VRC, UMB, Emory, Oxford UK, Mali
Canada, US, Gabon, Switzerland, Germany
Treatment: Ebola Vaccines
All depend upon a viral platform and ebola genes - 3
C. Ad26-EBOV/MVA EBOV– J&J, Janssen, and Bavarian Nordic - Adenovirus 26-EBOV prime boosted by MVA
NEJM Oct 2014
VRC, UMB, Emory, Oxford UK, Mali
Canada, US, Gabon, Switzerland, Germany
Treatment: Ebola Vaccines
Lancet ID 2016,16(1):31-42
Treatment: Ebola Vaccines
Treatment: Phase 2 Ebola Vaccines
Sierra Leone Guinea
Design- Head to head
GSK vs. Merck vs. None
9000 volunteers
Design- Wedge
HCW primarily
6000 volunteers
Design- Ring Design
Vacc ~50 surrounding contacts of each case
9000 volunteers in two arms (early vs. late)
Liberia
Treatment: Phase 2 Ebola Vaccines
Guinea
Design- Ring Design
Vacc ~50 surrounding contacts of each case
9000 volunteers in two arms (early vs. late)
Lancet 2015, 386:857
Helminth Vaccines
Blood flukes:Schistosoma mansoni, hematobium, etc.
Liver flukes:Fasciola hepaticus, Clonorchis, Opisthorchis, etc.
Intestinal flukes:Fasciolopsis, Echinostoma , etc.
Lung flukes:Paragonimus
Enterobius vermicularis
Ascaris lumbricoides
Hookworm spp.
Trichuris trichiura
Strongyloides stercoralis
Taenia spp. Echinococcus granulosis
Diphyllobothrium latum
Hymenolepsis diminuta
Hymenolepsis nana
2 billion people infected
300 million suffer severe morbidity
400 million school-aged children infected
40% of all infectious disease burden (minus malaria) derives from STH
The BIG Three: Hookworm, Roundworm, Whipworm
Soil Transmitted Helminths: Epidemiology
Rapid Impact Package: Praziquantel, albendazole, ivermectin and azithromycin = US$ 0.40. 7 of NTDs cured and 7 of 8 Millenium Development Goals addressed
No commercially available human helminth vaccines exist
One veterinary vaccine exists: Huskvac (oral lungworm vaccine for calves) produced from radiation-attenuated L3 Dictyocaulus viviparus
Soil Transmitted Helminths: Epidemiology
STH associated DALYs
Soil Transmitted Helminths: Hookworm
Ancyclostoma duodenale(0.15 mL per worm per day)
Necator americanus(0.03 mL per worm per day)
Adult hookworms: 1 cm in length40-160 hookworms sufficient to cause anemia/malnutrition. Lifespan: ~5 (Ad) and ~1 years (Na)Children sustain physical and intellectual impairmentTreatment: Albendazole or mebendazoleReinfection occurs within 4 months
Soil Transmitted Helminths: Hookworm
740 million infectedHeavy infections (>5000 eggs/gm stool) associated w/ 9 mL loss/day73% of worldwide severe anemia assoc. with hookworm
Hookworm Vaccine: Rationale
STH prevalence (a) globally and; (b) in China
Antihelminthic drugs failing
No immunity garnered. Adults have high hookworm prevalence.
Very high reinfection rates documented.
Emerging albendazole resistance – single mutation in tubulin allele
Albendazole therapy failure - Mali and China
Hookworm Vaccine: Feasibility
Stage Development of HookwormEnvironmental Parasitic
Egg L2 L3 (infective) L4 L5 (adult) Egg
Feasibility of Vaccine Approach 1 (Larval L3 proteins):Live L3 inocula elicit immunity (Johns Hopkins – 1930s-40s)
Attenuated (irradiated) L3 inocula in dogs cause 60-80% reduction of infection upon challenge – led to a licensed vet vaccine in 1973
Anti-ASP-2 IgE antibodies associated with reduced risk of heavy hookworm burden in Brazil and China (Bethony, 2005, FASEB J, 19:1743)
L3 proteins (cloned and expressed)45 kDa Ancyclostoma secreted protein 1 (ASP-1)23 kDa Ancyclostoma secreted protein 2 (ASP-2)62 kDa Ancyclostoma secreted metalloprotease (MTP)
Hookworm Vaccine: Human Trials
Human Hookworm Vaccine Initiative (Peter Hotez and David Diemert)
Na-ASP-2 Hookworm vaccine
21.3 kDa recombinant antigen cloned from N. americanus larvae
Expressed in yeast (Pichia pastoris) adsorbed to Alhydrogel®
Phase I study in healthy human volunteers – Immunogenic and well tolerated IM dosing on Days 0, 56, and 112. (D.Diemert, Sabin Institute)
Phase I study in healthy Brazilan adults conducted – reactogenicity noted
(Immediate-type hypersensitivity - Generalized urticaria within 1-2 hours)
All larval-stage antigen-based vaccines halted
Hookworm Vaccine: Adult worm secreted proteins
Na-GST-1
Aim - Want high IgG but
LOW IgE
Hotez et al., Nat Reviews 2010
IgE levels
Hookworms express proteases (cysteine, aspartic, and metallo-proteases). Localize to brush border of worm intestine. Digest Hb and serum proteins.
Rationale: Neutralize proteases involved in parasitic feeding and “starve” the worm.
Na- glutathione S-transferase-1 (GST-1)
Critical enzyme that enables parasitic feeding
Phase I testing in humans
Infect Immun, 2010
Hookworm Vaccine: Adult worm secreted proteins
Schistosomiasis (Bilharzia)
Water-borne blood fluke: S. mansoni, S. mekongi, S. haematobium, S. japonicum, S. intercalatum
200 million infected worldwide in 77 countries
20 million have severe disease
Each species has a predilection for a different venous plexus
1.
5 minutes after skin penetration, cercariae penetrates epidermis
2.
10 minutes after penetration, the cercariae has penetrated basementmembrane
3.
20 minutes after penetration, the cercariae has penetrated dermis
Mating pairs are egg production factories, generally living 5-8 years but potentially surviving for 30 years. End-stage sequelae of schistosomiasis occurs over decades of infection with large socio-economic tolls but still accounts for only a fraction of those w/ dz.
Male
Female
Chronic Schistosomiasis
S. mansoni/intercalatum: Inferior mesenteric venous plexus
Hepatosplenomegaly, granuloma/fibrosis, pancytopenia, GI ulcers, periportal fibrosis (4-8%) and portal hypertension. Rare cor pulmonale and neuroschistosomiasis
S. haematobium: Vesicular venous plexus. GU pathology, bladder calcifications and cancer.
Schistosomiasis Vaccine: Rationale
1. Vaccines provide cost-effective control for infectious diseases
2. High level protection is noted with irradiated cercariae injection
3. Chemotherapy has proven ineffective due to rapid reinfection
4. Drug resistance has formed and infrastructures in the developing world have proved inadequate for repetitive drug therapy
Vaccine Development:First attempts began 50 yrs ago: Crude worm extracts
Attenuated cercariae vaccination (1960s): >90% mice, 86% primates Theory: a proportion of larvae enter skin-draining lymph nodes inducing intense immune response.
Science – April 26, 2013
Sh Phase I vaccine-28 kDa GST-1
Completed 1989 –published 2012 (Phase II and III nearly complete)
Other candidates -Sm-14 used for fatty acid synthesis (Brazil – good abs but results not replicated)
Sm-TSP-2 (US – Sabin Institute)
Schistosomiasis Vaccine: Tetraspanins
Proteins prominent in outer tegument of schistosomes – function unknown
TSP-1 and TSP-2 (antibodies to TSP-2 are very high in putatively resistant and non-existent in chronically infected individuals) (Tran, Nat Med, 2006, 12:835)
Mice vaccinated with TSPs had reduced worm and egg burden:
TSP-1 - 34% adult worms53% egg burden
TSP-2 - 57% adult worms 64% egg burden
(Tran, Nat Med, 2006, 12:835)
Further helminth vaccine efforts are underway……….
Trichuris trichiura (whipworm)
Trichinella spiralis (trichinosis)
Onchocerca volvulus (river blindness)
Echinoccocus granulosus** (hydatid disease)
Cysticercosis** (Taenia saginata, T. ovis, T. solium) – application primarily directed as veterinary vaccines using DNA technology
Funding is a major obstacle to vaccine researchLarge philanthropies have not yet funded vaccine-related efforts.
Public-private partnerships (PPPs) are essential for accelerating NTD research towards vaccine development.
Acknowledgements:
SANARIAMALARIA ERADICATION THROUGH VACCINATION