Polio eradication has remarkably enhanced its level despite the COVID-19 pandemic. the restrictions on travel and movement during the pandemic contained the spread of poliovirus in endemic countries — Afghanistan and Pakistan. Even circulating vaccine-derived poliovirus (cVDPV) cases that accounted for many polio-related paralyses in recent years, have dropped.
But the impact of the pandemic on health and routine immunisation systems might make it tougher to stay the planet polio-free, even after the last case. To avoid recurrence, polio vaccines will be administered long after polio is eradicated.
The first case of untamed poliovirus in Africa in additional than five years underlines the danger of infections in the future.
Thousands of biological samples round the world should still contain live polioviruses. Some immunocompromised children got oral polio vaccines, which have a weakened live poliovirus, and that they might keep shedding the virus for the remainder of their lives.
We must now consider stopping polio recurrence, by integrating polio prevention into immunisation systems. According to WHO’s Strategic Advisory Group of Experts on Immunisation (SAGE) meeting in October 2021, acknowledged that “countries have different epidemiological risks and supported the utilization of injectable polio vaccine (IPV)-only schedules in countries in polio-free regions with high routine immunisation coverage…that conceive to withdraw bivalent oral polio vaccine (OPV) before certification of eradication”.
As routine immunization systems are under stress, the SAGE said that once adequate supplies are available, countries could consider adopting hexavalent (six-in-one) vaccines, as soon as they attempt to modernize their Expanded Programme on Immunisation, by increasing the IPV regimen from two to a few or more doses. Hexavalent vaccines can reduce the number of injections, making vaccination more acceptable to oldsters.
As far as the Countries in Europe and North America are concerned they have all been using combination vaccines for several years. But most countries currently using oral polio vaccines depend upon a unique style of combination vaccine — a whole-cell vaccine, to forestall pertussis or respiratory disorder. These combination vaccines when used have complex manufacturing processes and are something very challenging to formulate.
Future shortages of combination vaccines, and possibly of the IPV containing combination vaccine, seem highly likely, as confirmed through an independent modelling exercise. It takes five years or more, from getting to the primary vials of a vaccine being shipped; and far longer for producers to recoup the massive investments required. But still most of the vaccine purchases are made on shorter tenders, with uncertainty about demand without any consideration.
Among the teachings from COVID-19 is that the planet must plan better to handle infectious diseases. Polio is one of humanity’s oldest foes. The efforts of Extraordinarily brave immunisation workers have almost wiped it out. We must plan now to form sure that it can never come.