A sharp decrease in polio cases is expected as a result of an ongoing nationwide anti-polio immunization campaign in Tajikistan, according to the World Health Organization (WHO).
“During the immunization campaign we are vaccinating all children under six, which is about 1.1 million children. We are sure that the result of these three rounds will be a decrease of infected cases,” Cristiana Salvi, a spokesperson for WHO in Tajikistan, told IRIN in the capital Dushanbe.
The first round of the campaign ended on 8 May 2010, the second round will take place on 18-22 May and the third is slated for 1-5 June.
According to WHO, as of 9 May, Tajikistan had reported 278 cases of acute flaccid paralysis (AFP), the most common sign of acute polio but also associated with a number of other pathogenic agents. Of these, 56 have been laboratory confirmed as cases of wild poliovirus type 1 (WPV1) - of which 52 are in children under the age of six – and five others have been confirmed negative for poliovirus. The remaining cases are still being determined.
“We have two confirmed deaths,” said Salvi. “We are investigating the deaths among the suspected cases but we cannot confirm polio in those cases until we get laboratory confirmation.”
This is the first polio outbreak in what WHO calls the ‘European region’ after it was declared a polio-free zone in 2002.
So far, all AFP cases have occurred in southwestern Tajikistan - bordering Afghanistan, a polio-endemic country - and Dushanbe.
On 23 April, WHO said that genetic sequencing has determined that the WPV1 found in Tajikistan is most closely related to viral strains previously identified in Uttar Pradesh, India, another polio-endemic country.
First Russian cases
Russia, Tajikistan’s main trade partner and home to an estimated one million Tajik economic migrants, has reportedly banned the entry of all children under six from Tajikistan.
According to some media reports on 14 May, two polio cases, the first in five decades, have been confirmed in Russia recently – one in Irkutsk and the other in Moscow. Both patients are newly arrived baby girls from Tajikistan.
In a blog posted on 13 May, Allana Shaikh, a Tajikistan-based public health expert and blogger, said: “Tajikistan should simply not be seeing a polio outbreak. An 82 percent vaccination rate is enough to achieve herd immunity and protect even the unvaccinated.”
The World Health Organization and Centers for Disease Control and Prevention put the herd immunity threshold for polio at 80-86 percent, meaning if this proportion of the population is immune to the disease, it should theoretically no longer persist.
“There are several ways that the health system could fail on vaccination,” said Shaikh. “Vaccine records could be inaccurate, causing unvaccinated children to be missed by the system. Or the cold chain is not being maintained and the vaccines are losing effectiveness – the oral polio vaccine is especially vulnerable to warm temperatures. Whatever happened, it’s a sign of a health system weakness and the Ministry of Health of Tajikistan will need support to improve it.”
rk/at/ed
“During the immunization campaign we are vaccinating all children under six, which is about 1.1 million children. We are sure that the result of these three rounds will be a decrease of infected cases,” Cristiana Salvi, a spokesperson for WHO in Tajikistan, told IRIN in the capital Dushanbe.
The first round of the campaign ended on 8 May 2010, the second round will take place on 18-22 May and the third is slated for 1-5 June.
According to WHO, as of 9 May, Tajikistan had reported 278 cases of acute flaccid paralysis (AFP), the most common sign of acute polio but also associated with a number of other pathogenic agents. Of these, 56 have been laboratory confirmed as cases of wild poliovirus type 1 (WPV1) - of which 52 are in children under the age of six – and five others have been confirmed negative for poliovirus. The remaining cases are still being determined.
“We have two confirmed deaths,” said Salvi. “We are investigating the deaths among the suspected cases but we cannot confirm polio in those cases until we get laboratory confirmation.”
This is the first polio outbreak in what WHO calls the ‘European region’ after it was declared a polio-free zone in 2002.
So far, all AFP cases have occurred in southwestern Tajikistan - bordering Afghanistan, a polio-endemic country - and Dushanbe.
On 23 April, WHO said that genetic sequencing has determined that the WPV1 found in Tajikistan is most closely related to viral strains previously identified in Uttar Pradesh, India, another polio-endemic country.
First Russian cases
Russia, Tajikistan’s main trade partner and home to an estimated one million Tajik economic migrants, has reportedly banned the entry of all children under six from Tajikistan.
According to some media reports on 14 May, two polio cases, the first in five decades, have been confirmed in Russia recently – one in Irkutsk and the other in Moscow. Both patients are newly arrived baby girls from Tajikistan.
In a blog posted on 13 May, Allana Shaikh, a Tajikistan-based public health expert and blogger, said: “Tajikistan should simply not be seeing a polio outbreak. An 82 percent vaccination rate is enough to achieve herd immunity and protect even the unvaccinated.”
The World Health Organization and Centers for Disease Control and Prevention put the herd immunity threshold for polio at 80-86 percent, meaning if this proportion of the population is immune to the disease, it should theoretically no longer persist.
“There are several ways that the health system could fail on vaccination,” said Shaikh. “Vaccine records could be inaccurate, causing unvaccinated children to be missed by the system. Or the cold chain is not being maintained and the vaccines are losing effectiveness – the oral polio vaccine is especially vulnerable to warm temperatures. Whatever happened, it’s a sign of a health system weakness and the Ministry of Health of Tajikistan will need support to improve it.”
rk/at/ed
This article was produced by IRIN News while it was part of the United Nations Office for the Coordination of Humanitarian Affairs. Please send queries on copyright or liability to the UN. For more information: https://shop.un.org/rights-permissions
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