introduction of new vaccines hib as an example st. petersburg 25-27 jun 2001

Introduction of New vaccines

Hib as an Example

St. Petersburg25-27 Jun 2001

Vaccines use in the world• For the past two decades, in most developing

countries, vaccination restricted only to the initial EPI vaccines

• Where-as in most developed countries, several new vaccines such as HepB, Hib, meningococcal, pneumococcal, were gradually added to the initial EPI vaccines,

• Thus widening the gap in protection against infectious diseases between the rich and the poor

Number of Childhood Vaccines Routinely Used in Developing and Established Market Countries

5

6

7

8

9

10

11

12

13

1975 1980 1985 1990 1995 2000

Established Market

Developing CountriesVaricella

Acell pertussisPneumococcal *meningoccoal C*

MeaslesDPTPoliomyelitisBCG

Hepatitis B**

MeaslesMumpsRubellaDPTPoliomyelitis

Haemophilus InfluenzaeHepatitis B

*Estimated future use **Used in ~ 50% of global birth cohort

Estimated rate (children<5)

> 200/100,000100-200/100,00045-100/100,000< 45/100,000

Hib meningitis and pneumonia burden

Countries using Hib vaccine in their national immunization system, 2000

Why this difference?• Failure to demonstrate efficacy in

developing country settings early in the course of vaccine development;

• Lack of disease burden data, or awareness of disease burden in developing countries

• Failure to account for production for the developing world

Why this difference?

• Relatively higher prices of new vaccines; and

• Lack of technical advice and guidance on introduction of new vaccines

Proportion of Countries introducing Hep B and Hib, by per capita GNP

>$6000$1000-$6000

<$1000

0

20

40

60

80

%HibHep B

Causes of death in children less than 5 years old

ARIDiarrheaVPDPerinatalOther

19%

20%

20%

13% The Global Burden of DiseaseMurray and Lopez, editorsTotal - 12.8 million

Bacterial Meningitis

• Haemophilus influenzae type b (Hib)– 30% -50% of bacterial meningitis

• Pneumococcus– 25- 35% of bacterial meningitis

• Meningococcus – 25 - 35% of bacterial meningitis (except

during epidemics)

Pneumonia

• Haemophilus influenzae type b (Hib)– 20-25% of all severe bacterial pneumonia– Gambia, Chile, other studies pending

• Pneumococcus– ? 50-60% of severe bacterial pneumonia– South Africa, Gambia, Philippines, etc

• Others (RSV, adenovirus, etc)

Hib in the world

• Global burden of disease– Most common cause of bacterial meningitis in

children – Second most common cause of serious

bacterial pneumonia in children less than five years of age

– Total - estimated 400,000-500,000 deaths/year in children less than five

Hib vaccines: Safety and Effectiveness

• Hib vaccines are safe and easily administered within existing regimens

• Hib vaccines have high efficacy against:– Meningitis– Pneumonia– Bloodstream infections– Carriage

• Hib vaccines have prevented disease in unimmunized persons (‘herd immunity’)

Hib vaccine efficacy studies: Protection against invasive

disease

0%10%20%30%40%50%60%70%80%90%

100%

Gambia Chile USA USA UnitedKingdom

• Hib vaccines have proven their effectiveness in careful studies in Africa, South America, No. America and Europe

• Hib vaccines provide 90-100% protection against invasive Hib disease

Hib Conjugate vaccines

• Eliminate bacterial meningitis as a public health problem

• Reduce largest single remaining cause of infant mortality (pneumonia) by over 80%

• Safe, immunogenic and highly effective

• Widely used in industrialized countries

Hib vaccine efficacy in the Gambia: Protection against pneumonia and invasive

disease

0

10

20

30

40

50

60

Cases

prevented

Invasive Disease X-ray pneumonia

HIB cases prevented

95% efficacy

21% efficacy

Source: Mulholland et al. Lancet 1996

Impact of Hib vaccineon Hib meningitis in Uruguay

0

10

20

30

40

50

60

1991 1992 1993 1994 1995 1996

Year

No. Cases

Source: PAHO

Routine Hib vaccination started - with ‘catch up’

Other conjugate vaccines already in use

• Meningococcus– routine infant immunization in UK, Spain,

Ireland

• Pneumococcus– routine infant immunization in USA

WHO European Region

Mean annual incidence of Hib meningitis per 100 000 in children <5 years of age

3028 27 27

2220 19

1715

13 12 119 8 8 8 8 7 7 6 6

1 1

14

0

10

20

30

40

50

60

70

Sweden

Switzer

land

Denm

ark

Finlan

d

Nethe

rland

s UK

Israe

l

Slovak

ia

Franc

e

Austri

a

Repub

lic o

f Ire

land

Sloven

iaM

alta

Germ

any

Spain

Italy

Greec

e

Russia

n Fed

erat

ion

Czech

Rep

ublic

Poland

Bulgar

ia

Hunga

ry

Latvi

a

Region

al m

ean

The situation in CEE, NIS•From available data, Hib does not appear to be a major public health problem

•This could be real or fictitious

•If fictitious, the reasons could be

–problem in the collection of csf

–lack of lumbar puncture for suspected cases

–problem with laboratory technique

Where do we go?

• Surveillance for Hib disease

• Further studies

• Hib immunisation needs for special situations- day care centres, special paediatric units

The available tools

• Generic protocol for Pop based Hib studies

• HibRAT for quick assessment of the Hib burden based on retrospective analysis of laboratory data

• Management guidelines for those countries that are already using the vaccine