Inactivated polio vaccine support

In September 2014, Nepal became the first country to introduce inactivated polio vaccine with Gavi support.
Credit: UNICEF Nepal/2014.

The Vaccine Alliance works with the Global Polio Eradication Initiative (GPEI) to support one of the fastest roll-outs in the history of vaccination: the introduction of at least one dose of inactivated polio vaccine (IPV) into the routine immunisation schedules of all Gavi-supported countries.

Nepal became the first country to introduce the vaccine with our support in September 2014 – just 10 months after the programme was initiated. All 71 eligible countries have been approved for IPV support. By the end of 2017, 55 had successfully completed their introductions, collectively immunising more than 75 million children.

IPV coverage in Gavi-supported countries more than trebled from just 13% in 2015 to 43% in 2017.

Global polio eradication efforts

When the Global Polio Eradication Initiative (GPEI) was launched in 1988, polio was endemic in 125 countries and paralysed about 1,000 children per day. Thanks to global efforts and vaccination, polio cases have fallen by 99% since then, from an estimated 350,000 cases per year to 22 reported cases in 2017.

Today, more than 16 million people are walking who would otherwise have been paralysed by the poliovirus. Only parts of three countries – Afghanistan, Nigeria and Pakistan – remain polio-endemic.

Phased removal of oral polio vaccines

To eliminate the risk of vaccine-derived polio cases, the Polio Eradication and Endgame Strategic Plan calls for the phased removal of oral polio vaccines (OPV) by 2019 – a critical step towards polio eradication. The process started in April 2016 with the “global switch” – the replacement of trivalent OPV, containing type 2 virus, by bivalent OPV, comprising poliovirus types 1 and 3 only.

To minimise the risks associated with the switch, WHO recommended that all countries introduce at least one dose of IPV into their routine immunisation schedule before the transition. IPV provides protection against all three poliovirus types.

SAGE also recommends that countries consider vaccinating children who were missed since the switch, as they are currently not protected against poliovirus type 2. Gavi supports countries that decide to implement these recommendations.

More affordable prices

Following a 2014 tender for IPV, the vaccine is available to Gavi-supported countries from as little as €0.75 per dose. Middle-income countries are able to buy the vaccine through UNICEF for between €1.49 and €2.40 per dose.

Crippling, potentially fatal

Polio is a highly contagious viral infection, mainly affecting children under the age of five, which can lead to paralysis or even death.

Many infected people have no symptoms but they still excrete the virus, transmitting infection to others. In areas with poor sanitation, the virus easily spreads through contaminated water or food.

One in 200 infections leads to irreversible paralysis, usually in the legs. Among those paralysed, 5–10% die when their breathing muscles become immobilised.

Polio can only be prevented with a vaccine, as there is no cure. Multiple doses are required, usually providing life-long protection.

Supply constraints

The sheer pace and scale of inactivated polio vaccine (IPV) introductions, coupled with the technical difficulties of scaling up production capacity, have led to severe supply constraints. As a result, 16 Gavi-supported countries had not yet managed to introduce the vaccine by the end of 2017, 14 had to discontinue their programmes and 2 introductions were significantly delayed.

Although the supply situation is improving, and some countries have since been able to resume their programmes, it is likely to remain fragile until 2020.

WHO’s Strategic Advisory Group of Experts (SAGE) has advised countries to consider switching to fractional doses of IPV. This approach, adopted by Bangladesh, India and Sri Lanka, ensures protection while reducing the risk of vaccine stock-outs.

POLIO’S FINAL MILE

Today, Pakistan and Afghanistan carry the burden of wild polio cases, but as outbreaks in Ukraine and Mali have shown, a weakened health system and persistent low immunisation coverage rates can quickly reverse the gains.

In May 2013, the World Health Assembly endorsed the new Polio Eradication & Endgame Strategic Plan 2013–2018, calling on countries to introduce at least one dose of the inactivated polio vaccine (IPV) and begin the phased removal of oral polio vaccines (OPV).

All countries successfully switched from the trivalent OPV to the bivalent OPV in April 2016 – removing the type 2 component of the vaccine as type 2 wild poliovirus has already been eradicated. This, in turn, will lead to the complete removal of the live-attenuated oral vaccine, which is necessary to eliminate the risk of vaccine-associated polio outbreaks.

The introduction of IPV is a critical step to manage potential risks associated with this phased removal. Adding IPV to routine immunisation programmes will improve immunity and help to prevent further OPV-associated outbreaks from emerging.

The Global Polio Eradication Initiative has extended its deadline for eradicating polio from 2018 to 2021. This, combined with global shortages of supply of IPV has led the Gavi Board to extend the support for IPV from 2018 to 2020, subject to additional funding being made available.

Supporting the Polio Endgame

To complement the efforts of the Global Polio Eradication Initiative (GPEI), Gavi is using its experience in supporting new vaccine introductions to facilitate the rapid roll-out of inactivated polio vaccine (IPV). This will help meet the unprecedented timelines of the Polio Eradication and Endgame Strategic Plan.

Gavi supports the introduction of IPV with funding from GPEI in eligible countries and helps to strengthen routine immunisation programmes.

IPV introduction

The Vaccine Alliance continues to support one of the fastest roll-outs in the history of vaccination: the introduction of at least one dose of IPV into the routine immunisation schedules of Gavi-supported countries.

Countries introducing IPV receive a one-time cash grant from Gavi, funded by GPEI, to support some of the additional activity costs related to introducing the new vaccine. These activities may include health worker training, social mobilisation, micro-planning, expansion or rehabilitation of cold chain equipment, printing of materials (such as immunisation cards), technical assistance and modifications to the surveillance systems.

The Global Polio Eradication Initiative has extended its deadline for eradicating polio from 2018 to 2021. This, combined with global shortages of supply of IPV has led the Gavi Board to extend the support for IPV from 2018 to 2020, subject to additional funding being made available.

STRENGTHENING ROUTINE IMMUNISATION

Strengthening routine immunisation is a pillar of the polio eradication strategy. High coverage provides a strong base for population immunity to prevent polio outbreaks and builds a sustainable platform for the introduction of IPV and other life-saving vaccines.

In polio-endemic countries, the virus persists in marginalised populations where health and immunisation services are largely non-existent, and where oversight and management of primary health care systems are weak.

However, the poliovirus cannot survive for long periods outside the human body. Without an unvaccinated person to infect, the polio virus will die out. As a result, strengthening routine immunisation is a critical factor in successfully interrupting all poliovirus transmission.

Gavi is working with GPEI and other key partners to strengthen routine immunisation in 10 focus countries targeted by the Polio Endgame Strategy. The countries (Afghanistan, Angola, Chad, DR Congo, Ethiopia, India, Nigeria, Pakistan, Somalia, South Sudan) all have significant numbers of partially and non-vaccinated children.

These efforts benefit from the expertise developed by GPEI since 1988 to support and strengthen broader immunisation activities.