As global polio cases continue to mount compared to the past two years, with some countries like China and the Philippines reporting new polio cases after decades of polio free status, Sri Lanka is on the verge of polio eradication due to her consistently maintaining a 99% high routine vaccination coverage. “The last case of poliomyelitis (Polio) due to wild polio virus was in 1993. Thereafter, there has been no new polio cases to date. We have been polio free for the past two decades,” says Consultant Epidemiologist, Epidemiology Unit, Ministry of Health, Dr Deepa Gamage. She noted that Sri Lanka could become a zero polio nation if she continues to maintain the high routine vaccination coverage under the Expanded Immunisation Program.
n this interview with the Sunday Observer, Dr Deepa Gamage explains how Polio impacts on the health of a person and the significant role vaccination plays to help fight the disease , as well as interventions by the Ministry to maintain the country’s polio free nation status.
Excerpts…
Q. Several polio outbreaks have been reported globally this year. What is Sri Lanka’s position in this situation?
A. The last case of poliomyelitis (polio) due to wild polio virus was in 1993. Thereafter, we did not have any polio cases. This is because our parents have for the past several years shown keenness to vaccinate their children with polio vaccine enabling the country to maintain a high vaccination coverage of nearly 99%.
All newborns in the country are identified, registered for vaccination and followed up with the relevant doses.
Q. What is Polio? What causes it?
A. Polio is a disease of paralysis, caused by a deadly virus, which belongs to the Picornaviridae family. This virus has three types called sero types, named polio virus 1, 2 and 3. Acutely induced flaccid paralysis of children can happen by all 3 sero types.
However, now all polio cases caused by this wild polio viruses are due to polio virus type 1. Wild polio virus type 2 has been declared eradicated in 2016 and wild polio virus type 3 is declared eradicated only this year, on October 24 as a World Polio Day message.
Whatever the polio virus type, the clinical presentation of the disease is the same.
Q. What are the consequences of becoming afflicted with it?
A. Once the virus enters the body, through oral route, it multiplies in the gut if not immunised for polio. Then it enters the blood stream and disseminates all over the body.
The polio virus has special preference to damage nervous tissues. This causes paralysis of children. It can also cause death of the affected due to respiratory muscle paralysis, nervous system damage involved in the respiration, or complications of the paralysis. Long term disabilities due to paralysis causes problems to children throughout their life. It is an immense social problem for parents in taking care of the long term disabled child due to poliomyelitis.
Q. Who are most at risk age wise?
A. Most vulnerable age categories are the children under five years, if they have not gained adequate immunity or are not protected from polio viruses through vaccination.
Q. How can we identify whether polio infected children exist in the country?
A. We conduct Acute Flaccid Paralysis surveillance. That means, all polio like paralyzed cases are tested for polio in stool samples in the Polio Virology Laboratory at the Medical Research Institute and are excluded based on the results of negative report and clinician’s diagnosis of some other disease. In this process all Paediatricians, Physicians, Neurologists, Microbiologists and Virologists in hospitals inform the under 15 paralyzed to the field level Medical Officer of Health (MOH) of the patient’s residence as a mandatory notification requirement. These MOHs and Public Health Inspectors (PHI) visit the affected patient’s house and carry out field level investigations to ensure there are no further cases and all the contacts of the case are healthy and vaccinated for polio. This is how we know that polio is no more in the country.
Polio virus can transmit while being hidden without causing external signs; and of 200 infected one child could get the paralysis. This shows the easily possible transmission of polio virus from infected persons without external signs or symptoms.
Q. To maintain immunity against the disease how many polio vaccinations are recommended in the national schedule?
A. All children should be vaccinated with Oral Polio Vaccination (OPV) and Inactivated Polio Vaccine (IPV). OPV should be given at 2,4,6,18 and 60 months as five doses. Injectable IPV should be given at 2 and 4 months as two doses. The child will then be fully protected for life.
Q. The South East Asia Region( SEAR) to which Sri Lanka belongs has been declared and certified as Polio free in March 2014, in line with achieving the goal of world free of Poliomyelitis. Tell us more about this program.
A. The South East Asia Region is declared and certified as polio free after March 2014, in line with achieving the goal of world free of Poliomyelitis. Polio Eradication through Polio Endgame strategies had been planned to achieve by 2018. Because of continued polio cases in Afghanistan and Pakistan, this target could not be achieved and is extended to 2023 for polio eradication.
Q. In addition there is also the Global Polo Eradication Initiative. Tell us more about it.
A. The Global Polio Eradication Initiative (GPEI) was started in 1988 with the aim of global polio eradication, extending the eradication target years and the most updated target of polio eradication to be achieved by 2023. But, the continued polio transmission is a big challenge in polio eradication. The GPEI identified Polio Vaccination and Acute Flaccid Paralysis are main strategies to be implemented in achieving polio eradication.
Q. What are your biggest challenges in this respect?
A. If vaccination is not at optimal level, polio virus can easily transmit to a country. Therefore, routine immunization has to be continued for all the children. Because of the global travel patterns and high tourism experienced in Sri Lanka, there is a high chance of polio virus transmission into the country and children could get affected if they are not properly vaccinated.
Q. Can transmission be prevented in ways other than the vaccine? How?
A. Polio virus transmits faeco-orally. Polio virus excrete in stool once infected enters the body through oral route. Unhygienic conditions and poor sanitary conditions, can easily transmit it. However, polio vaccination as recommended for the National schedule is the most important. This is usually provided through the MOH office clinics by the Public Health Midwives and hospital immunization clinics under the guidance of Paediatricians by Immunization clinic nursing officers.
This polio vaccination of OPV provides gut immunity and once the virus enters through the oral route, it will not enter if gut immunity is maintained.
If the virus escapes from the gut, serum immunity is necessary to protect the nervous system. That is why both types of polio vaccines (OPV and IPV) are important.
Proper hygiene and sanitation is the most important preventive strategy in addition to vaccination. Safe drinking water, hygienic food habits, personal hygienic measures such as proper hand washing with soap and water before meals and after toilet use, prevention of open defecation are important measures in preventing polio virus transmission.
Q. The Polio Immunisation program has been described as one of Sri Lanka’s success stories. Your comments?
A. As you observed Immunization against Poliomyelitis is the success story in Sri Lanka. Following the first major epidemic in 1962, the oral polio vaccine was introduced to the country. The OPV vaccine was introduced into the National EPI in 1974 and high OPV coverage maintained above 95% in all districts in the country for the last 10 years or more.
Supplementary immunization with OPV, in National Immunization Days, Sub National Immunization Days and Mopping up campaigns were conducted since 1995-2003 in achieving high population-level polio immunity and maintenance of polio-free status in the country.
Q. What further actions have been taken to maintain polio free status?
A. The Epidemiology Unit of the Ministry of Health, is the central coordinating centre for the implementation of National Immunization Program and National AFP Surveillance Program under the Poliomyelitis Eradication Initiative, receiving information about AFP cases (under 15 years) from clinicians in curative institutions.
The virology laboratory in the Medical Research Institute (MRI) is the Reference Laboratory doing investigations in the laboratory in the exclusion of polio in all AFP cases.
Q. Since travellers from polio endemic countries or countries where there has been an outbreak pose a threat to transmission here, what precautions have you taken to prevent or reduce this danger?
A. We have traveller guidelines, in which travellers and those who intend a long term stay in a polio endemic or polio infected countries are advised to get the polio vaccination. Globally compulsory vaccination for those going out of the country is considered only for Pakistan which is considered a ‘possible polio exporting country.’
However, we recommend polio vaccination for all travellers going out of the country in to polio endemic and infected countries. This polio vaccination for travellers can be got from Port Health Offices and evidence of the vaccination will be an international certificate.
Q. Your message in brief to the public?
A. Vaccinate all children with both OPV and IPV and adhere to safe drinking water and food habits.