Polio is a highly communicable viral infection that can cause paralysis. The disease has been all but eliminated in the developed world but remains a global threat. Immunization against polio is essential to protect populations from this debilitating disease. Recent advances have made the vaccine more effective and easier to administer. According to William D King, continued investment in polio immunization programs is critical to achieving global eradication of the virus.
William D King Lists Recent Advances in Immunization Against Polio
Since the 1950s, immunization against polio has been one of the most successful public health interventions. The introduction of IPV – inactivated poliovirus vaccine – in 1955 and live oral poliovirus vaccine (OPV) in 1963 led to a dramatic decline in the incidence of polio globally. As a result of these vaccines, the last endemic case of wild polio was reported in Nigeria in 2016.
However, even though wild polio has been eradicated, there is still a risk, according to William D King, of outbreaks from cVDPVs – circulating vaccine-derived polioviruses. cVDPVs are derived from OPV and can lead to paralysis, just like wild polio. Outbreaks of cVDPV have been reported in several countries, most recently in the Democratic Republic of Congo (DRC) and Madagascar.
The World Health Organization (WHO) has responded to these outbreaks by recommending a switch from OPV to IPV. The use of IPV will help to reduce the risk of cVDPV outbreaks and eventually lead to the complete eradication of polio.
Inactivated poliovirus vaccine (IPV) is a vaccine that contains inactivated (killed) polioviruses. It is given by injection and is the only type of polio vaccine currently recommended for use in the United States.
IPV was first licensed in 1955 and has been used routinely in the United States since 1963. It is usually given as a 4-dose series, with each dose given at least 1 month apart. The first dose is typically given when a child is 2 months old, followed by doses at 4, 6–18 months, and 4–6 years. A booster dose of IPV may be given at 4–6 years of age if it has been 5 or more years since the last dose of IPV.
Live oral poliovirus vaccine (OPV) is a vaccine that contains live, attenuated (weakened) polioviruses. It is given by mouth and is no longer recommended for use in the United States.
OPV was first licensed in 1963 and was used routinely in the United States until 2000 when it was replaced with IPV as the routine polio vaccine. OPV is still used in other countries where polio is endemic, or there is a risk of importation of wild-polio virus.
Circulating vaccine-derived polioviruses (cVDPVs) are derived from live oral poliovirus vaccines (OPV). They are called “circulating” because they are able to spread from person to person and can cause polio outbreaks.
cVDPVs have been reported in several countries, says William D King, most recently in the Democratic Republic of Congo (DRC) and Madagascar. The World Health Organization (WHO) has responded to these outbreaks by recommending a switch from OPV to IPV. The use of IPV will help to reduce the risk of cVDPV outbreaks and eventually lead to the complete eradication of polio.
The last endemic case of wild polio was reported in Nigeria in 2016. As a result of vaccination with inactivated poliovirus vaccine (IPV) and live oral poliovirus vaccine (OPV), the incidence of polio has declined dramatically globally.
William D King’s Concluding Thoughts
These recent advances in immunization against polio are very promising, according to William D King. It is important that we continue to support these efforts in order to ensure that this disease is eradicated worldwide. With the right resources and commitment, we can make this happen.