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The State of Vaccine Confidence

The State of Vaccine Confidence

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Confidence Commentary: Blog archive

Is the “big switch” the final piece in the polio jigsaw?

Heidi Larson | 29 Apr, 2016

Click here to view the original Thomson Reuters Foundation post.

Last week’s launch of the global polio eradication initiative’s “big switch” has garnered wide interest among the public and the media, and rightly so. According to the World Health Organization the simultaneous switch from trivalent to bivalent oral polio vaccine is the largest vaccine rollout in history with 155 countries involved. To complete the goal of ridding the world of polio this should be one of the final pieces in the jigsaw.

However, three days after the initiative was launched a less well reported event occurred in Pakistan that serves as a stark reminder of the challenges still remaining. The news of seven policemen being attacked and killed while protecting polio vaccinators on their rounds in Karachi is distressing, but sadly not surprising.

Violent, often fatal, attacks in general, as well as specific attacks on polio workers and their security guards, have been a growing phenomenon and challenge to polio eradication.

Despite the challenges and continuing volatile situation in both Pakistan and Afghanistan, there has been progress on polio, but history shows it is particularly fragile.

The total polio case count in 2015 was 54, down from 306 in 2014, but the 2014 high was a dramatic increase from a low of 58 in 2012. As of April 20, there have been eight cases of polio in Pakistan, compared to 21 at the same time last year. Afghanistan has had three cases in 2016 compared to only one case in April last year. A successful but bumpy road towards a world without polio.

From a global perspective, the eradication horizon has overcome considerable obstacles which offers hope for the current challenges in Pakistan.

Last year Nigeria marked one year without a case of polio, after years of working to overcome a damaging eleven-month boycott of the polio vaccination in Kano State and also having experienced violent fatal attacks on polio workers. India was certified as being polio-free in early 2014, after also facing pockets of vaccine resistance and refusals in Uttar Pradesh, the last state to harbour the polio virus.

While continuing to stay focused on ridding the last two endemic countries of circulating wild poliovirus, the big switch marks a new push closer to achieving full eradication.

Building on last year’s successful eradication of wild poliovirus type 2, the big switch aims to reduce the risk of vaccine-derived polio, 27 cases of which occurred last year alone. Stopping the use of trivalent vaccine, which targets poliovirus type 1, 2 and 3 and replacing it with bivalent vaccine which targets only types 1 and 3 is no easy task, nor is clearing all trivalent vaccine from storage cabinets and production facilities around the world, the switch’s other major aim.

In order to provide additional protection during the transition, the IPV (inactivated polio vaccine) is also being introduced. It is less potent than the oral polio vaccine, but cannot lead to vaccine-derived polio. Ninety-four of the 126 countries still giving oral polio vaccine, have also introduced the IPV vaccine, but another hiccup in the road to progress is a global shortage of the IPV vaccine supply.

Where does this leave us? Well polio transmission may not be stopped in 2016 as hoped but, if the world is not complacent, next year remains a very realistic target.

It’s unlikely to be a smooth journey but, as Nelson Mandela once said, “After climbing a great hill, one only finds that there are many more hills to climb.” The complex big switch and eliminating polio in Pakistan and Afghanistan are certainly high hurdles to overcome, but tough challenges are nothing new for the Global Polio Initiative.

Literature Literature archive

VK Phadke, RA Bednarczyk, DA Salmon, SB Omer. 2016. JAMA. 315(11):1149-1158 doi:10.1001/jama.2016.1353
YT Yang, PL Delamater, TF Leslie, and MM Mello. 2016. American Journal of Public Health. 106(1): 172-177. doi: 10.2105/AJPH.2015.302926.
BJ Vonasek, F Bajunirwe, LE Jacobson et al. 2016. PLoS ONE. 11(2):e0150131. doi: 10.1371/journal.pone.0150131

Videos Video archive

Drs. Larson and Paterson join a discussion on vaccine confidence at Hong Kong University.  September, 2015.

Dr. Larson’s address to the CSIS conference on “The Global Experience in Addressing Cervical Cancer”.

Dr. Larson discusses the VCP’s 2015 report on the State of Vaccine Confidence worldwide.

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