Saturday marks the 30th World's Strengthened Immunity Day, a day which was originally set to eliminate poliomyelitis or polio.
Polio is a highly infectious disease caused by poliovirus, spreading from person to person. Children under five are the main victims, and one in 200 may suffer irreversible paralysis.
In 1988, a global polio eradication initiative was launched and over 99 percent of the cases were eradicated. However, polio still exists "among the world's poorest and most marginalized communities, where it stalks the most vulnerable children," according to the World Health Organization (WHO).
Polio vaccine is the main and effective way to prevent the disease, as more than 16 million people have been saved from paralysis thanks to vaccination efforts, said the WHO. Before the advent of the vaccines, almost every child would be infected by the poliovirus.
'Sugar pills' in childhood
Sweet sweet "sugar pill" to prevent polio, December 5, 2014. /VCG Photo
Many Chinese may still have the memory of the so-called "sugar pills" in their childhood, which actually is an oral polio vaccine (OPV) for prevention.
China started its nationwide vaccination of OPV since 1965, and the number of polio cases has plummeted ever since.
The country didn't see any cases caused by indigenous wild poliovirus in 1994 and was certified by the WHO as a polio-free country in 2000, according to the Chinese Center for Disease Control and Prevention, or China CDC.
Trivalent oral polio vaccine (TOPV), known as the "sugar pills" in China, protects against poliovirus types 1, 2, and 3. But it is no longer in use and replaced by bivalent oral polio vaccine, as type 2 poliovirus was wiped out.
Inactivated polio vaccine (IPV) is another form to protect against poliovirus, by injection.
Polio vaccination continues despite no polio cases
A Yemeni child receives a polio vaccination during an immunization campaign at a health center, November 26, 2018. /VCG Photo
Polio transmission in any country will put their children under risk.
Though there's no indigenous wild poliovirus case in China, the virus hasn't been eradicated worldwide.
The movement of the infected population can cause the spread of poliovirus across regions or borders and spread rapidly among non-immunized ones, said China CDC.
"Every child must be vaccinated to eradicate polio," the WHO highlighted. "The world can be freed of the threat of polio – with everyone's commitment, from parent to government worker and political leader to the international community."