Measures against polio intensify
Thailand stepped up precautionary measures against poliomyelitis yesterday after Laos declared a public health emergency due to the virus.
Amnuay Kajina, director-general of the Department of Disease Control (DDC), yesterday said even though Thailand is declared free of polio, Thais are still at risk of contracting the disease, particularly in provinces close to Laos.
Dr Amnuay said he instructed public health officers in border provinces where disease control checkpoints are located to intensify preventative measures.
People in border areas are required to receive polio vaccines. Acute flaccid paralysis patients and patients from Laos in border hospitals must be kept under close surveillance.
Preventive measures have intensified following the spread of vaccine-derived polioviruses (VDPVs) in Laos and Myanmar in recent months.
VDPVs are strains of the polio virus that have genetically mutated from the strain contained in the oral polio vaccine.
According to the DDC, authorities in Laos have rolled out two measures against polio. People living in Laos are required to receive polio vaccines one month before leaving the country.
The vaccine must also be administered to people planning to stay in Laos for more than a month.
Dr Amnuay said Laos has outlined the measures to the Thai Ministry of Foreign Affairs. The Interior Ministry and local administrative officials were also notified.
In April, Thailand and other countries will simultaneously switch from using the trivalent oral polio vaccine, which contains three poliovirus serotypes, to bivalent OPV in an effort to eradicate wild polio virus type 2.
Explaining how the vaccine works, Bureau of Epidemiology director Thanarak Plipat said the body digests the vaccine and the virus replicates in the intestinal tract, providing immunity from subsequent polio infections. The body will later shed the virus while defecating.
When the virus circulates in the body and environment for some time it can mutate, eventually causing poliomyelitis, Dr Thanarak said.