Microbe of the Month: Endangered, but not quite extinct: The virus that causes polio could go the same way as smallpox and be history by 2000, writes Bernard Dixon

THE WORLD Health Organisation has had to abandon its much-trumpeted goal of attaining 'health for all by the year 2000'. Poverty, military conflict, political and religious barriers and the emergence of diseases such as Aids have conspired to forestall such an achievement. But there is one WHO target that remains very much in sight. The virus responsible for poliomyelitis, which can cripple or kill its victims, could well be eliminated by the turn of the century.

At present, only one disease-causing microbe has been rendered extinct in nature - the smallpox virus, whose eradication the WHO announced in 1987 following a triumphant worldwide vaccination programme. The only surviving samples of the virus are held in secure laboratories in Atlanta and Moscow. Following discussions at the International Congress of Virology in Glasgow in August, the decision whether or not to destroy those stocks will be taken at the World Health Assembly in Geneva next May.

There are two principal grounds for believing that polio will follow smallpox into the textbooks of medical history. First, immunisation in both cases confers solid, long-lasting immunity. Even if the virulent virus is introduced into a vaccinated community, therefore, it cannot cause disease and has negligible chances of spreading or surviving. Second, poliovirus, like smallpox virus, does not infect or persist in any other living creature (as does the malarial parasite in mosquitoes).

Where immunisation has been widely deployed, it has already vanquished polio. In 1955, there were more than 76,000 cases of the disease in the United States, Canada, Australia, New Zealand, the Soviet Union and 23 European countries. By 1967 that figure had fallen to 1,013, and today polio is very rare in industrialised regions. These advances have come from two vaccines. The first, consisting of 'killed' poliovirus and given by injection, was developed by Jonas Salk and introduced in the late Fifties.

The second, a live but weakened virus taken by mouth, was devised by Albert Sabin and came into use in the early Sixties.

Today, each year, more than 80 per cent of the world's infants are immunised against polio. The problem for the WHO is covering the remaining 20 per cent, many of whom live in parts of the world that are

not easy to reach by mobile immunisation teams. Yet this was precisely the challenge that was faced and overcome in the crusade against smallpox.

But no battle is won until the enemy has been defeated. That is why public- health specialists have been warning that as long as even the smallest pockets of unvaccinated, or inadequately vaccinated individuals, exist, even the richest countries face the risk of sudden outbreaks. Dr David Carrington and colleagues at the Ruchill Hospital in Glasgow recently reported the results of a survey in which they showed that only a third of people tested in their city had adequate levels of antibodies against one of the three types of poliovirus. To ensure full protection, it is essential that everyone has received the full sequence of three doses of vaccine.

There is another problem, illustrated by the outbreak of poliomyelitis in the past year in the Netherlands, a country with one of the most efficient health services in Europe. As occurred in 1978-79, the epidemic arose in Protestant communities whose allegiance to the Dutch Reform Church leads them to refuse immunisation on religious grounds. Although the outbreak has been contained by offering immediate vaccination to school pupils and other people likely to have been in contact with members of the affected group, at least 68 people have had the disease, some suffering paralysis. The 1978-79 incident eventually affected 110 people, 80 of whom were paralysed. In neither case has the original source of the virus been pinpointed, although presumably it was imported from a part of the world where the disease is still endemic.

Ironically, religious leaders are one group the WHO has been urging to become involved in its global eradication efforts. The campaign has brought together disparate forces, from the cricketer Imran Khan, who has promoted immunisation in Pakistan, to Rotary International, which is raising funds towards the elimination of polio by 2005. Religious leaders would be a welcome addition to these forces.

A little subversion might help, too. There is a good chance that if the Netherlands had chosen the Sabin vaccine for its routine immunisation programme, at least some of the children now paralysed by polio would have escaped. This is because the living Sabin virus, unlike the killed Salk virus, is shed in the faeces of vaccinees. It is thus passed to other children, who become immunised without either their or their parents' knowledge.

Which prompts the question: should vaccine manufacturers, using the new techniques of genetic manipulation, now begin to design vaccines against other infections with just this aim in mind - the incidental vaccination of other children? Would that be common sense or an infringement of religious freedom?

(Photograph omitted)

Start your day with The Independent, sign up for daily news emails
peopleJonathan Ross has got a left-field suggestion to replace Clarkson
Andy Davidhazy at the beginning (left) and end (right) of his hike
Pandas may be more sociable than previously thought
Arts and Entertainment
The teaser trailer has provoked more questions than answers
filmBut what is Bond's 'secret' that Moneypenny is talking about?
ebooksA special investigation by Andy McSmith
Lewis Hamilton secured his second straight pole of the season
f1Vettel beats Rosberg into third after thunderstorm delays qualifying
Arts and Entertainment
Written protest: Julia Donaldson, author of The Gruffalo, has sent an open letter to the Culture Secretary
footballDoes Hodgson's England team have an identity yet?
travel Dreamland Margate, Britain’s oldest amusement park, is set to reopen
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Massage Therapist / Sports Therapist

£12000 - £24000 per annum: Recruitment Genius: A opportunity has arisen for a ...

Ashdown Group: Practice Accountant - Bournemouth - £38,000

£32000 - £38000 per annum: Ashdown Group: A successful accountancy practice in...

SThree: Trainee Recruitment Consultant

£18000 - £23000 per annum + Uncapped commission: SThree: Does earning a 6 figu...

Recruitment Genius: SEO Executive

£18000 - £25000 per annum: Recruitment Genius: This is an exciting opportunity...

Day In a Page

The saffron censorship that governs India: Why national pride and religious sentiment trump freedom of expression

The saffron censorship that governs India

Zareer Masani reveals why national pride and religious sentiment trump freedom of expression
Prince Charles' 'black spider' letters to be published 'within weeks'

Prince Charles' 'black spider' letters to be published 'within weeks'

Supreme Court rules Dominic Grieve's ministerial veto was invalid
Distressed Zayn Malik fans are cutting themselves - how did fandom get so dark?

How did fandom get so dark?

Grief over Zayn Malik's exit from One Direction seemed amusing until stories of mass 'cutting' emerged. Experts tell Gillian Orr the distress is real, and the girls need support
The galaxy collisions that shed light on unseen parallel Universe

The cosmic collisions that have shed light on unseen parallel Universe

Dark matter study gives scientists insight into mystery of space
The Swedes are adding a gender-neutral pronoun to their dictionary

Swedes introduce gender-neutral pronoun

Why, asks Simon Usborne, must English still struggle awkwardly with the likes of 's/he' and 'they'?
Disney's mega money-making formula: 'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan

Disney's mega money-making formula

'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan
Lobster has gone mainstream with supermarket bargains for £10 or less - but is it any good?

Lobster has gone mainstream

Anthea Gerrie, raised on meaty specimens from the waters around Maine, reveals how to cook up an affordable feast
Easter 2015: 14 best decorations

14 best Easter decorations

Get into the Easter spirit with our pick of accessories, ornaments and tableware
Paul Scholes column: Gareth Bale would be a perfect fit at Manchester United and could turn them into serious title contenders next season

Paul Scholes column

Gareth Bale would be a perfect fit at Manchester United and could turn them into serious title contenders next season
Inside the Kansas greenhouses where Monsanto is 'playing God' with the future of the planet

The future of GM

The greenhouses where Monsanto 'plays God' with the future of the planet
Britain's mild winters could be numbered: why global warming is leaving UK chillier

Britain's mild winters could be numbered

Gulf Stream is slowing down faster than ever, scientists say
Government gives £250,000 to Independent appeal

Government gives £250,000 to Independent appeal

Donation brings total raised by Homeless Veterans campaign to at least £1.25m
Oh dear, the most borrowed book at Bank of England library doesn't inspire confidence

The most borrowed book at Bank of England library? Oh dear

The book's fifth edition is used for Edexcel exams
Cowslips vs honeysuckle: The hunt for the UK’s favourite wildflower

Cowslips vs honeysuckle

It's the hunt for UK’s favourite wildflower
Child abuse scandal: Did a botched blackmail attempt by South African intelligence help Cyril Smith escape justice?

Did a botched blackmail attempt help Cyril Smith escape justice?

A fresh twist reveals the Liberal MP was targeted by the notorious South African intelligence agency Boss