Wednesday, September 3, 2014
One of the world’s leading experts on polio eradication says a recent announcement stating that a new strain of the disease is resistant to vaccines is incorrect.
The announcement, which came in the form of a press release from Passport Health, which claims to be the largest and leading provider of travel medicine and vaccination services in the North America, states, “A new report out of Germany shows that a new polio strain that killed 209 people in the Congo in 2010 might be able to overcome current polio vaccinations.”
Dr. Olen Kew, senior science advisor in the Polio and Picornavirus Laboratory Branch of the U.S. Centers for Disease Control and Prevention (CDC), in Washington, D.C., said the vaccines developed in the 1950s and ‘60s, and used today, work on all polio strains.
“Vaccines have worked everywhere in the world where they are used properly,” Kew said.
“The source of the strain described in the article was India. The virus in India has been eradicated.”
In fact, Kew stated, there are only two countries that have strains that have survived – Nigeria and Pakistan.
And that is because those countries are not administering the vaccines, he said.
Kew has worked for years in genetic genotyping to “finger print” the virus and determine where each strain is coming from.
He said there are three types of polio strains, two of which, Type 2 and 3, have been eradicated completely.
Type 1 is the only type that has strains that have not been eradicated. But even those strains can be prevented with proper use of the vaccines.
Kew said it is very important that people vaccinate their children to prevent the spread of polio and that it is required by law, unless religious beliefs reject immunization.
“Polio has been introduced in the U.S. many times but has not caused outbreaks, except in groups that refused vaccination,” Kew said.
“As recently as the 1980s, Mexico had polio circulating, but we were protected.”
He said some groups of people decline immunization because of misinformation and put children at risk.
“Some people thought immunization causes autism, but that has completely discredited and the researcher who published that study had his license revoked because he falsified information,” Kew stated.
“That had a ripple effect and caused children to die unnecessarily.”
According to the Global Eradication Initiative, polio is a crippling and potentially fatal, highly infectious disease. There is no cure, but there are safe and effective vaccines.
The strategy to eradicate polio is therefore based on preventing infection by immunizing every child until transmission stops and the world is polio-free.
Polio (poliomyelitis) is caused by a virus. It invades the nervous system and can cause irreversible paralysis in a matter of hours.
Polio can strike at any age, but it mainly affects children under five years old.
Polio is spread through person-to-person contact. When a child is infected with wild polio virus, the virus enters the body through the mouth and multiplies in the intestines, the Global Eradication Initiative website states.
It is then shed into the environment through the feces where it can spread rapidly through a community, especially in situations of poor hygiene and sanitation.
If a sufficient number of children are fully immunized against polio, the virus is unable to find susceptible children to infect, and dies out, the website states.
Young children who are not yet toilet-trained are a ready source of transmission, regardless of their environment.
Polio can be spread when food or drink is contaminated by feces. There is also evidence that flies can passively transfer polio virus from feces to food.
“In developing countries, the threat is mostly from fecal to oral transmission,” Kew stated.
“If a country has poor water, the disease can spread rapidly.”
Kew said in the 1940s in the United States, before vaccines were used, children were not allowed to go to the movies together or swim together in pools.
“Direct exposure to respiratory droplets can spread polio, so close crowding of kids was not allowed,” he said.
Most people infected with the polio virus have no signs of illness and are never aware they have been infected. These symptomless people carry the virus in their intestines and can “silently” spread the infection to thousands of others before the first case of polio paralysis emerges, the Global Eradication Initiative website states.
For this reason, health officials consider a single confirmed case of polio paralysis to be evidence of an epidemic – particularly in countries where very few cases occur.
Most infected people (90 percent) have no symptoms or very mild symptoms and usually go unrecognized. In others, initial symptoms include fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs.
In the early 20th century, polio was one of the most feared diseases in industrialized countries, paralyzing hundreds of thousands of children every year, according to the Global Eradication Initiative website.
Soon after the introduction of effective vaccines in the 1950s and 1960s however, polio was brought under control and practically eliminated as a public health problem in these countries.
It took somewhat longer for polio to be recognized as a major problem in developing countries.
Lameness surveys during the 1970s revealed that the disease was also prevalent in developing countries.
As a result, during the 1970s, routine immunization was introduced worldwide as part of national immunization programs, helping to control the disease in many developing countries.
For more information, visit www.polioeradication.org.