Monday, December 3, 2007

Time to introspect

Its time to introspect and reflect upon the strategies that have been taken up towards polio eradication. World Health Organizations’ (WHO) commitment to global eradication of poliomyelitis by the year 2000 has failed leaving India as one of the four countries where the deadly polio virus is still prevalent making polio –free India a distant dream.

In spite of combined and consistent endeavors by UNICEF, National Polio Surveillance Project, Indian Academy of Pediatrics and Rotary International, our nation still reels under this vaccine preventable disease. We must therefore learn and implement the measures that have been taken by the industrialized countries to achieve zero polio status.

Health experts from Indian Academics of Pediatrics (IAP) and the World Health Organization (WHO) have recommended the use of Inactivated Polio Vaccine (IPV) used in industrialized countries, in combination with Oral Polio Vaccine for better immunization against the dreaded polio disease. The major advantage of using IPV being that it does not carry the risk of VAPP (vaccine-associated paralytic polio) which is caused by the administration of OPV. OPV being made of live virus carries with itself the danger that the attenuated form can revert to its virulent form and result in paralysis which can cripple the affected individual for life. Though there is a small chance of an infant being infected with polio while receiving OPV drops, however, the more the OPV drops, the greater the risk.

Other than the risk of acquiring VAPP, oral polio vaccine loses its effectiveness in conditions of poor sanitation and thus this is the primary reason why polio still persists in Uttar Pradesh. Poor hygienic conditions perpetuate diarrhea and this high occurrence of diarrhea interferes with OPV administration making it difficult for the body to retain the oral polio vaccine long enough to develop immunity. Moreover, there is an aversion towards OPV administration amongst some sections in Uttar Pradesh because of the myth that it leads to impotency. The latter is resulting in a crisis since a majority of children are being missed out owing to spread of this myth as the houses are either found locked or the health workers are not welcomed when the surveillance teams come for administration.

Keeping in mind, the repercussions of using OPV alone, there is a dire need to move to a combination of both IPV and OPV. IPV not only carries away the risk of acquiring VAPP but also provides individual immunity. It provides better humoral immunity compared to OPV and triggers and excellent immune response and long lasting immunity to all the 3 types of polio virus strains. Moreover, it can stay effective even without proper cold storage facility for a longer time span. According to health experts, in the endemic areas, 2 doses of IPV would be more effective than 10 doses of OPV as immunization with IPV triggers an excellent immune response in most IPV recipients. They also state that that OPV (Oral Polio Vaccine) should not be administered to a child with immunodeficiency or to a child who is in close contact of a person with immunodeficiency and instead should be given IPV.

Thus, its time to focus and change our strategies, that is, make use of IPV per say to be able to achieve zero polio status like other countries because we cannot wait for a catastrophe to happen. It is suggested by health experts that IPV alone should be made use of in states which have been polio free for 3-6 years while a combination of OPV and IPV should be used in polio-ridden states. The time has come to make the right choice and protect our children from this crippling disease.

Monday, November 26, 2007

Know Polio for No Polio

Fight against the dreaded disease actually begins with knowing what we are up against

What is polio?

Polio [PO-lee-oh] or poliomyelitis is a viral disease that can damage the nervous system and cause paralysis.

What is the cause of polio?

Polio is caused by any of the three types of polio viruses-- Poliovirus type 1 (PV1 or Mahoney), PV2 (Lansing), and PV3 (Leon). The polio virus lives in the throat and intestinal tract of infected persons. The polio virus enters the body through the mouth, usually from hands contaminated with the stool of an infected person. Sharing contaminated utensils, can also spread the virus.

Is Polio a world-wide phenomenon or restricted to a few countries?

Till a few decades ago, polio was one the world’s most deadly diseases crippling and maiming people all over the world. However due to massive global immunization programs and eradication efforts, polio has been limited to a decreasing number of countries. The greatest risk is now in the Indian subcontinent and, to a lesser extent, in West and Central Africa.

What are the symptoms of polio?

The worst part is that many people infected with the virus have few or no symptoms. The polio virus attacks the nerve cells that control muscle movements causing headache, tiredness, fever, stiff neck and back, and muscle pain. More serious problems happen when the virus invades nerves in the brain and causes paralysis of the muscles used in swallowing and breathing. Invasion of the nerves in the spinal cord can cause paralysis of the arms, legs, or trunk.

How long does it take after the exposure for symptoms to appear?

Usually it takes 7 to 14 days for the symptoms to appear after exposure to the virus. A person with polio can spread the infection as long as the virus is active in their throat or stool. The virus can be found in the throat 1 week after infection and in the stool for 6 weeks or longer.

How is polio diagnosed?

Polio is diagnosed by a blood test or culture.

Who is at risk for polio?

Polio is most common in infants and young children, but complications occur most often in older persons.

What complications can result from polio?

Complications include paralysis, most commonly of the legs. Paralysis of the muscles that control breathing and swallowing can be fatal. In very rare cases, the oral vaccine used to prevent polio can cause polio paralysis in persons who are vaccinated (1 in every 8.1 million doses) and in people who are close contacts of a vaccinated person (1 in every 5 million doses).

What is the treatment for polio?

There is no treatment for polio. A polio patient must receive expert medical care, especially at the beginning of the illness.

How can polio be prevented?

Polio is preventable by immunization. Two types of polio vaccine are available: oral polio vaccine (OPV) and inactivated polio vaccine (IPV). OPV is made with a live but weakened virus. OPV protects vaccinated persons directly. OPV also protects other susceptible persons who are indirectly "vaccinated" as the vaccine virus spreads in the community. Because of wide use of OPV, no cases of paralytic polio caused by naturally circulating polio virus have been reported in the United States since 1979.

IPV is given by injection. The latest thinking worldwide is to give a combination of OPV and IPV for effective protection against polio. The recommended schedule for polio vaccination for children is two doses of IPV at 2 and 4 months of age, followed by two doses of OPV at 12-18 months and 4-6 years. This is expected to reduce the small number of polio cases caused by the oral vaccine.

Booster doses of polio vaccine are also recommended for persons traveling to polio affected areas of the world.

This information is for patient awareness only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health-care provider. For more details consult your family physician or health-care provider

Tuesday, October 23, 2007

What makes Polio a dreaded disease?

The scariest thing about polio is that 95 percent of people infected with the polio virus do not exhibit any symptoms. Yet while they themselves do not display any symptoms, they can still spread the polio virus and cause others to develop polio.

The Poliovirus can strike at any age, but affects mainly children younger than three. It is spread by poor sanitation and infected drinking water. Early symptoms are fever, fatigue, headache, vomiting, stiffness and pain in the neck and limbs.

The poliovirus attacks the central nervous system, leaving victims with fever, permanent muscle weakness, paralysis and, in extreme cases, death from asphyxiation.The virus generally enters the body through the mouth and multiplies in the intestine. The polio virus in the nervous system can cause total paralysis in a matter of hours.

Polio is caused by three poliovirus serotypes-- Poliovirus type 1 (PV1 or Mahoney), PV2 (Lansing), and PV3 (Leon). Out of these Type-2 poliovirus appears to have has been eliminated.

Treatment of Polio focuses on providing relief of polio symptoms as the body fights the poliovirus. This is called supportive care.

If there is one disease that illustrates the value of vaccination, it is Polio. Typically the fight against Polio starts with building up the body’s immune system to fight the disease through immunization. Under the Global Polio Eradication Initiative -- the largest public health initiative the world has ever known, 130 million children around the world are immunized before the age of five.

When it comes to immunization there are only two options – oral drops (OPV) or injectable vaccine (IPV). Among these, the oral polio vaccine developed by Polish American scientist Dr. Sabin, has been preferred in many countries because it is administered orally -- usually on a sugar cube. This also does not require a highly trained person to administer the dose i.e. two drops in the mouth.

Dr. Sabin believed that the polio viruses lived in the small intestines. So he developed a mutant form that could not reproduce the disease, but would displace more lethal forms of the virus. Rather than subject another person to risk, Dr. Sabin ingested the mutant virus himself to prove its effectiveness.

The Salk vaccine on the other hand needs to be injected with a needle. These injections require administration by trained medical personnel. There is also resistance among poor, illiterate people to get their children “pricked by needles”.

One of shortcomings of the oral vaccine is that the attenuated virus used in the vaccine may revert to pathogenicity, causing paralysis in one out of every 750,000 to 2.5 million people vaccinated, depending on the source. Rarely, a strain of poliovirus in OPV may genetically change and circulate among a population. These are known as vaccine-derived polioviruses (VDPV) and knowledge on them is growing.

On the other hand,IPV is not a 'live' vaccine - the polio virus is inactivated - and immunization with IPV carries no risk of vaccine-associated polio paralysis. The injectable vaccine contains three viral strains in the following proportions: 40 units of type 1; 8 units of type 2; and 32 units of type 3. Generally speaking, the oral vaccine contains one live, attenuated strain of each type.

Because of these reasons alone in countries where the risk of wild-virus caused polio has come down to zero immunization programmes are now considering combined immunization schedule using both OPV and IPV.

In countries where there is only one type of virus in circulation (generally type 1, but also type 3), the WHO recommends using a monovalent vaccine). Monovalent oral polio vaccines (OPV) – targeted at poliovirus types 1 or 3 – appears to work faster than traditional trivalent OPV to build immunity.

Friday, October 19, 2007

Mission: Polio Free Planet Earth

For nearly 6,000 years now, since the time of the Ancient Egyptians, Polio (also known as poliomyelitis or infantile paralysis) has been one of the most dreaded diseases crippling and maiming mostly children, with a frightening randomness. Records on Paranoiac stele show that the disease existed in Egypt more than 3000 years ago. Withered and deformed limbs of Egyptian mummies are an evidence for this. An Egyptian stele (stone slab) dating back to the 18th paranoiac dynasty (16th - 13th centuries B.C.) shows a priest leaning on a staff, his right leg withered and dangling. His foot is in the equines position, which is a typical sign of polio.

Till as late as 1700's, however, existence of polio remained a mystery even in medical science. The first clinical description of polio dates as far back as 1789 when British physician Michael Underwood referred to it as "debility of the lower extremities."

Polio remained the No 1 most notorious diseases in the 20th century till AIDS arrived on the horizon. Even today the crippling virus accounts for nearly 20 million disabled and paralyzed people in six of the world's poorest nations.

A major breakthrough in the fight against Polio came in 1948 when a research group headed by John Enders at the Children's Hospital Boston successfully cultivated the poliovirus in human tissue in the laboratory. This development greatly facilitated vaccine research and ultimately allowed for the development of vaccines against polio. Enders and his colleagues, Thomas H. Weller and Frederick C. Robbins, were awarded Nobel Prize for Medicine in 1954

A turning point in the history of polio came with the introduction of an inactivated polio vaccine (IPV) in 1955. This contained an inactivated or "killed" version of the virus. This vaccine had to be administered by injection. On April 12, 1955, Dr Jonas Salk, developed a vaccine to prevent polio. This was followed by launch of the oral polio vaccine (OPV) by Dr Albert B. Sabin in 1961. Unlike the injectible form, the oral polio vaccine containing a live attenuated, or weakened, version of the virus. This Sabin vaccine had to be given orally.

Another significant landmark in the fight against polio came in 1988, with the launch of the Global Polio Eradication Initiative. This initiative was instrumental in curtailing the toll of polio paralysis from an estimated 350,000 cases worldwide to fewer than 500 in 2001. Thanks to the hard work of millions of volunteers, the commitment of governments everywhere and the dedication of international partners, nearly four million people have been spared crippling lifelong disability. This was a sharp contrast from the times when wild polio virus was paralyzing more than 1000 children every day in more than 125 countries across five continents. Today polio is largely confined to Nigeria, India, Pakistan, Niger, Afghanistan and Egypt.

But the battle for a polio free world seems to be far from over. The lethality of Polio can be judged from the fact that even today there is no treatment, anywhere in the world. Polio is caused by poliovirus. Till date there is no antibiotic or medicines which can completely and effectively kill the polio virus.