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International Vaccine Access Center Blog


This article was originally published in Open Magazine and is cross-posted here with permission. 

This post is part of the #ProtectingKids blog series. Read the whole series here.PATH2015_BlogSeries

Niya Zameen with her two boys outside their home in Ramsar

Niya Zameen, 33, lives with her two sons in Ramsar, in Barmer district of Rajasthan. Her village has a population of just 1,078 and is close to the India-Pakistan border. Niya has always tried to ensure that her children receive the necessary healthcare services, including vaccines, to give them a healthy start in life. Getting her children vaccinated hasn’t always been easy because of shortages of government recommended vaccines. But Niya has never given up. With the help of the local health worker, Rampatti, she made sure that her children received the necessary vaccines against measles, polio, and three doses of diphtheria-tetanus-pertussis. 

IndianBoyImmunizedOf the 1.3 million Indian children under-5 that died in 2013, pneumonia claimed more than 175,000 lives and diarrhoea caused more than 130,000 deaths. Even in cases of survival, the severe burden of illness from diarrhoea and pneumonia adversely impacts children’s growth and development. But many of these severe illnesses can be easily prevented through immunisation. The pentavalent vaccine, that prevents a deadly form of pneumonia and meningitis, is now available through government immunisation programmes in some states and the vaccine to tackle diarrhoea caused by rotavirus, will soon be rolled out.

Niya Zameen acknowledges the crucial role that Rampatti, the local health worker, plays in her life. She has provided guidance on important health decisions, including the role of vaccines in giving all children protection against preventable diseases.

Vaccine delivery is a challenge in this region, due to extremely hot weather and the difficult desert terrain. If the vaccines don’t arrive on the designated day of immunisation, Rampatti travels to the vaccine cold chain point to collect them for her village. On her return, she vaccinates children. 


Every child has the right to a healthy start, and it is the responsibility of not just the government, but also of the community to ensure that all our children are timely and fully immunised.

Photos by Shikha Nayyar

By Dr. Kate O’Brien

Today is a landmark day, one that many global health experts thought might not happen. Today marks three years since the last case of wild polio in India, the requirement to officially certify the country, and with it the WHO South-East Asia Region, polio-free. While the official declaration is not due until March when a WHO Regional Certification Committee reviews all the data, today is a day to celebrate and to be remembered in India and around the world for years to come.


Photo Credit: Rotary International

It is a day to congratulate India, but also the global community. It is a day that gives us all strengthened hope and confidence in achieving the goal of global polio eradication. In 1998, India had a high of nearly 2,000 cases of paralytic polio from the wild poliovirus, and as recently as 2009, it still was home to most of the world’s polio cases. By 2011, it had wiped out wild polio cases, and now it has maintained that status for three years. India’s large, dense, and often migratory population combined with poor sanitation conditions in parts of the country created some of the most difficult conditions throughout the world to control disease. However, with a depth of commitment from all levels of government and civil society and dedication of significant resources, India achieved this mammoth goal. It could not have been done without the work of millions of individuals, including the 2.3 million vaccinators, the thousands of clinicians and epidemiologists in more than 33,000 surveillance sites, the religious leaders and advocates committed to on-the-ground outreach, and the leaders across government and industry who together contributed nearly US$2 billion in funding.   

Thanks to all of these individuals, India is now polio-free, and its triumph over polio is a massive public health achievement---one that will leave a lasting impact on children's health in India and around the world. It is also a testament to the power of immunizations, which have been saving lives in India and around the world for centuries.

India has achieved a laudable reduction in global child deaths in recent years, and vaccines have been one of the most effective interventions in this effort. Not only have vaccines prevented deaths, but they’ve also helped children stay healthy and averted crippling social and economic costs to families and society. Beyond polio, India’s other great achievements related to vaccines are highlighted in this infographic.


Vaccines clearly work and they clearly work in India. As coverage levels increase and new vaccines are introduced into its Universal Immunization Programme, disease reduction will amplify, and children will lead healthier, longer lives. These inspiring efforts should be applauded along with India’s polio achievement.

India’s achievements should also inspire the global community to rededicate our efforts to ensure every child around the world is protected from preventable diseases. We have a unique window of opportunity to change history by eliminating polio from the three remaining countries where transmission has not yet been stopped – Pakistan, Afghanistan, and Nigeria – and maintaining disease control in other countries where elimination is fragile and polio threatens to return. With much learned from India’s success, communities, countries and the global community have a strong, actionable plan to achieve a polio-free world by 2018.

Ending polio everywhere, forever, is a critical step toward improving the lives of the world’s most vulnerable children. As India has clearly shown, polio eradication can lead the way for other child health initiatives, by strengthening surveillance systems, building networks of trained community health workers, and engaging leaders from across diverse disciplines. The job is not yet done; India and other countries around the world will need to sustain and continue to build on the progress to date while planning for the next step of introducing at least one dose of inactivated polio vaccine.

The remaining polio-endemic countries should have a deep sense of hope, bolstered by the accomplishments and lessons learned in India, that this goal is at their fingertips.  The scientific, public health, communication, and organizational tools are in place. With the right political will, polio will be wiped out; there will remain substantial and at times unanticipated challenges to match the accomplishment of India in the remaining countries, but these are surmountable. There is a lot to be optimistic about. India has demonstrated to the world what is possible when the community in all its dimensions – local and global, political and religious, scientific and lay – has a common commitment. We call on all partners to continue without wavering the march toward worldwide polio eradication and in so doing achieve the purest measure of health equity.


Kate O’Brien, MD, MPH, is Executive Director of IVAC. A pediatric infectious disease physician, epidemiologist, and vaccinologist, she previously served as Deputy Director of IVAC. She also serves as Associate Director of the Center for American Indian Health.


Daniel Feikin, MD, MSPH

Special thanks to Daniel Feikin, MD, MSPH, for sharing his insight on his team’s latest publication. Dr. Feikin has been with the U.S. Centers for Disease Control and Prevention (CDC) for 15 years, where he spent 6 years with the Respiratory Diseases Branch and also served as the Epidemiology Section Chief for the International Emerging Infections Program in Kenya.  Dr. Feikin has worked on a number of projects including surveillance establishing the burden and epidemiology of respiratory and diarrheal illness.  Since 2010, Dr. Feikin has served as the Director of the Epidemiology team at the International Vaccine Access Center (IVAC).

Published in the September issue of PLOS Medicine, Serotype-Specific Changes in Invasive Pneumococcal Disease after Pneumococcal Conjugate Vaccine Introduction: A Pooled Analysis of Multiple Surveillance Sites analyzes the rates of invasive pneumococcal disease after the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7).  Dr. Feikin and colleagues from IVAC and CDC conducted this meta-analysis which showed that a reduction in all-cause and vaccine-type invasive pneumococcal disease happened rather quickly and was sustained for seven years after the introduction of PCV across the study sites.  In the following interview, Dr. Feikin shares his insight on the issue of serotype replacement and how this it relates to decision making regarding PCV use.

What is serotype replacement (SR) and why is it an issue?

We have a unique situation with pneumococcus and pneumococcal vaccines with respect to serotype replacement. With pneumococcus, serotypes are defined by the kind of sugar capsule that surrounds the bacterium, and 90 different types have been defined.  This creates a challenge for vaccines, which are based on specific serotypes. The first iteration of this conjugate vaccine could only fit in seven serotypes.  They put the seven most common serotypes that you’d find in the US and Europe into the vaccine – that covered about 85% of the disease in the U.S.

First, SR was observed in the nose, which is where pneumococcus resides. Most of the time, the bacteria doesn’t cause disease, it just lives there in back of the nose (the nasopharynx) and a small percentage of the time, the bacteria in the nose will go on to cause an infection. When you get vaccinated, you get rid of the seven pneumococcal serotypes contained in the vaccine from the nose – quite effectively and quite rapidly.  But what we also saw was that the seven serotypes that were wiped out by the vaccine were replaced by other serotypes of pneumococcus.  That phenomenon – when you get rid of [serotypes] and they are replaced by others – is dubbed SR.  The concern was: this is what happens to the bacteria living in the nose; does the same thing happen with disease caused by those bacteria?   Are you just getting rid of the disease caused by the seven serotypes in the vaccine and having it be replaced by pneumococcal disease (PD) from the other serotypes?  If that were to happen, you have the paradoxical situation of a vaccine that works against the seven serotypes you want it to work against, but your overall disease rates might not change in the long run because of SR.  It was a really important question about whether this vaccine had an overall impact on disease – we needed to clarify whether SR exists and how much it exists.

What type of study did you choose to look at this issue and why did you feel it was the best way to research this question?

We conducted a meta-analysis, using 21 databases that were identified, to look at IPD rates after PCV7 introduction. When you are considering PD, you have to think about several different types of disease. The first type of disease is called invasive pneumococcal disease (IPD).  IPD is the most straightforward because it means bacteria have invaded a normally sterile site – usually the cerebrospinal fluid, (the fluid surrounding the meninges) or the blood – and you can grow the bacteria from this fluid so it can be detected and positively identified. But the much bigger burden of PD is pneumonia, and most of the time when you have pneumococcal pneumonia you’re not going to isolate the bacteria since you can’t get a sample from the lung to grow and it normally isn’t a sterile site. So, when you want to look at SR, you are limited to looking at IPD – where you are able to culture the pneumococcus. That’s why the study focuses on IPD. 

The second thing to understand is that there have been lots of individual studies from different countries, or different sites from the same country, that have looked at the issue of SR. There were many reports that came out after vaccine introduction and they were variable.  There were some sites that showed very little SR and big impact of the vaccine. Then, there were other studies that showed up to full SR, meaning that you get rid of the vaccine serotype [with] full replacement by non-vaccine serotype (NVT), so in those sites there were no changes in overall disease rates.

This led to a lot of confusion. As countries in Africa and Asia were thinking about introducing PCV, they were concerned and somewhat confused about this issue of SR and wanted to know if PCV was worth their investment. That was the impetus in doing the study and it’s unclear why there were different results in different places. Some of it might have been that there truly was more SR in some sites, but it also could have been methodological differences or that some sites had very small samples sizes. One outlier site was potentially getting a lot of attention and people were looking at that saying there was complete SR, whereas another site was not showing that. So the idea behind the study was to put all the sites together, weigh all the studies according to their size and findings, and see if we could come up with some sort of summary of SR.

In the course of this analysis, was there anything that was surprising to you?

I have two answers for that. First, although a lot of countries had introduced PCV7, there weren’t many sites that had done the type of surveillance that we felt would be appropriate for this type of analysis. There were sites that were doing surveillance, but when you boiled it down to who met stringent criteria for being able to evaluate SR, there weren’t as many as I thought. That was a lesson because people are out there publishing studies and making conclusions about SR with limitations in their surveillance, which we felt would affect their interpretation of SR, so we did not include those types of studies. We were fairly rigorous in our inclusion and exclusion criteria, so we only ended up including 21 studies. 

The second thing that was somewhat surprising to me in the results was that when we looked at children, and when we looked at the overall impact of this vaccine on children, there was about a 50% reduction in overall IPD. So, overall IPD decreased by half. We saw that decrease happen by the first year after the vaccine was introduced and it stayed at roughly 50% reduction all the way out to about seven years. I thought that initially there would be a growing reduction in overall PD over time. The drop in the first year was greater than I thought – suggesting that this vaccine had a pretty fast impact on pneumococcal epidemiology in children – and it didn’t change a lot after that first year.  Now, there was a lot going on with each progressive year, so vaccine types started to go down and they continued to go down out to seven years until they were virtually gone. You were getting a lot of change in the different serotypes starting in the first year after vaccine introduction and continuing out, but changes in the vaccine types and changes in the NVTs balanced each other out, so this overall 50% reduction remained fairly consistent over the seven years.

How could this study contribute to policy making? 

I think that for policy makers (people that don’t think about PD everyday), I think their take-home point is that there’s about a 50% reduction in IPD in children and it lasts all the way out to seven years. There is SR; it exists. It’s a real phenomenon, but the proportion of disease caused by vaccine serotypes is greater than non-vaccine serotypes, so  the vaccines do have an overall impact on disease in children. I think that’s the first message.

The second is that you do see a herd effect in adults. There is a decrease in overall IPD in adults. It’s not as great as what is seen in children and it’s a bit delayed, but at least in the countries that introduced PCV, there was herd protection among adults – which could potentially have a big impact for countries, especially low-income countries, that have a lot of PD in adults. For a decision maker, hopefully that’s the message they get from this.

Are there any plans that you know of to build on the evidence provided by this study, and investigate SR in higher valency PCV?

There are some clear limitations to this study. The first limitation is that this study looked at the impact of the 7-valent PCV. That vaccine is no longer made.  Countries are introducing either 10-valent vaccine or 13-valent vaccine. Much of the SR that we saw occurring came from the six extra serotypes that were not in the 7-valent vaccine but are now in the higher valency vaccines, so we suspect that these higher valency vaccines would take care of a good deal of the SR that we saw. 

What we don’t know is: Are there other serotypes that are waiting in the wing that will cause SR in the same way? It would be important to follow countries as they introduce the higher valency vaccines and do a similar type of analysis several years out after the vaccine has been introduced. The problem is: we showed that you really need to go out to five or more years after vaccine introduction to see what exactly is going to happen to this dynamic process overtime. You can’t do the studies yet because the vaccines have just been introduced in the last couple of years so we need to wait, particularly for developing countries because they are just introducing.

The second major limitation is that the studies we looked at in our analysis were mostly from developed countries (North America, Europe, and Australia). There were a few indigenous populations in our data set – the Navajo and the Australian indigenous – which might be more like the low-income country populations, but not exactly the same. So, it is possible that in Africa and South Asia, where the epidemiology of PD is different, the results of the vaccine could potentially be different as well. It would be important to do a similar type of analysis in those countries. I think this type of analysis needs to be repeated in a few years, and it needs to be repeated in low-income settings that have the higher valency vaccines.

Do you have any other thoughts that you want to convey that we have not covered?

I think there is one thing, not based on the data itself, but just a comment. One of the things this study showed is the power of collaboration. Any single site would not be able to do this type of analysis, but they showed data from their own site and they made conclusions for their own site. But in order to understand an epidemiologic concept in a broader way that may vary site by site, you really need to have data from different places. The willingness of investigators to collaborate on this project, to lend their data to be looked at, to work together to make some sort of conclusion that was bigger than their own data was a really valuable exercise. This type of collaboration between sites is becoming more and more important, and we’re seeing more of it happening in the field of epidemiology. So, the example of doing a multi-site analysis, where sites give their data and they participate in the interpretation, was a valuable lesson and exercise.

This is the second in a series of profiles to help IVAC partners and friends get to know our team. This one features Chizoba Wonodi, an epidemiologist who leads IVAC’s Nigeria work. We caught up with Chizoba just before she made a big move back to Nigeria with her family. After living in Baltimore for 10 years, Chizoba will now represent IVAC in country, and she will dig deeper into efforts to work with the Nigerian government and other stakeholders to improve routine immunization and increase accountability.

Tell me a bit about your background and when you joined IVAC.

Before coming to Baltimore, I worked as a physician in Nigeria, concentrating mostly on adolescent sexual and reproductive health and HIV/AIDs prevention. I came to Johns Hopkins for my masters in public health and, after that, I went on to the DrPH (Doctor of Public Health) program, completing both programs as a Gates Institute Scholar. In 2006, in my third year of the doctorate program, a colleague introduced me to the PneumoADIP project that would later morph into IVAC. I thought the whole concept of accelerating access to vaccines was novel and cool and I wanted to be part of it. So I sought and got work as student research assistant with PneumoADIP.

When I graduated from my doctoral program in 2009, I joined the Hopkins faculty knowing I wanted to focus my work on Nigeria. My desire has always been to take what I learned at Hopkins and apply it to my home country. At IVAC, I have been able to do just that. My work is to support the Nigerian government in developing effective policies and programs to deliver life-saving vaccines to children. We work alongside many organizations, including the WHO and UNICEF, in helping the government build stronger immunization systems. We do this through policy and operations research, translating evidence to policy, and brokering or advocating for relevant interventions. Instituting accountability within the health system is also a big part of my work in Nigeria.


Chizoba Wonodi with her niece. (Photo credit: Tyrone Shoots)

What inspires you to work in global health? 

I think the potential to make a difference on a large scale drew me to global health.  I came to this realization after medical school, when it was time to choose a clinical specialty. I considered pediatrics because I love children, but I didn’t have the affinity for one-on-one interventions when thousands were dying of preventable causes. I wanted to change things at a broader level. With public health, you can see how the policies and programs you implement affect large populations. 

What does it mean for you to be doing work to help Nigeria?

It is a privilege because not everybody has the opportunity to come to Johns Hopkins, a world-class institution, and receive training from the best in the field and work beside them.  It is wonderful to be able to take what I learned here back to Nigeria and try to make a difference there. However, it isn’t just about taking knowledge back, but also learning from the dynamic changes that have occurred in Nigeria.

Can you explain the kind of dynamic changes Nigeria has gone through?

There is more human capacity than before. In the last decade, a crop of globally educated public health revolutionaries – if I may call them that – have returned home with cutting-edge knowledge, skills, and attitudes. They’ve melded the global perspective with their local knowledge and sensibilities and have become a force for change. They resist doing business as usual and push for decisions to be evidence-based. They are forging partnerships in unusual places, demanding accountability, and focusing on results not just inputs.


Chizoba Wonodi at the National Vaccine Summit in Abuja, Nigeria, April 2012. (Photo courtesy of Tyrone Gibson)

In the vaccine world to be exact, there has been a growing awareness of and greater access to new vaccines. For instance, Haemophilus influenzae type B (Hib) vaccine was introduced last year, hopefully next year, pneumococcal conjugate vaccine (PCV) will follow. Although it took more than 15 years for these new vaccines to become available in the country, the momentum is shifting rapidly as more stakeholders acknowledge the importance of immunization. In April 2012, we saw a massive outpouring of support and promises at the National Vaccine Summit. Many hands are now on deck to help prop up the routine immunization system, and we are seeing positive results. Top among the donors is GAVI, who provides the single largest investment in routine immunization in Nigeria. As more partners come on board, the program space gets crowded and the pace quickens. It is all very exciting. However, one has to be nimble and responsive, to be relevant.

What has been your most rewarding or memorable experience at IVAC?

Seeing the impact of the policies we’ve helped influence result in access to new vaccines for children has been most rewarding. I remember when I came to the PneumoADIP and we were working on the introduction of PCV into developing countries. At that time PCV was considered too expensive for poor countries, but by getting countries to recognize the burden of pneumococcal disease, by convincing vaccine manufactures that there was a market beyond Europe and America, and by mobilizing the right financing, we (and others) helped accelerate PCV introduction into Africa and Asia.

Six years later, it is gratifying to see PCV introduction has outpaced earlier projections. This means many more children (in the millions) are being vaccinated and protected than we ever thought possible. There aren’t many opportunities where you get to contribute to change as big as that.  


At the National Vaccine Summit in Nigeria (left to right): Dr. Ado Mohammad, Executive Director of the National Primary Health Care Development Agency; Dr. David Okello, former WHO Representative for Nigeria; and Dr. Chizoba Wonodi, Epidemiologist and Nigeria Projects Lead at IVAC. (Photo courtesy of Tyrone Gibson)

Wow, that sounds wonderful but also very demanding. What do you do in your free time to relax?

I like to cook. I watch the Food Network to learn new recipes. I love Asian food so I started learning to cook Chinese and now Korean food.

Speaking of cooking and eating, if you could have dinner with anyone – alive or dead – who would you pick and why?

I would choose Nelson Mandela. I don’t think there is anyone in the world as loved and as esteemed. I would like to feel the essence of the man and understand what makes him stand out so much. It would be a wonderful opportunity to learn from someone who has so much compassion, knowledge, and wisdom.

So through our conversation so far, it is obvious you are very proud to be Nigerian. What about Nigeria do you like best?

I love the people. We are proud and very happy people. In fact, there was a study that found Nigerians are the happiest people on earth. You wouldn’t think that given all our challenges and issues; but that is just who we are. We are very welcoming and very hospitable. And I love that when you meet a Nigerian, they proudly proclaim they are Nigerian.

What is your wish for Nigeria?

My immediate wish is that the 2015 elections will come and go flawlessly without any major upheavals. I also hope that the bloodshed in the north will stop so people can get back to living their lives. And I wish that Nigerian leaders would recognize and build our biggest resource – our human resources. Part of that includes making sure girls are educated. Once girls are educated, half the job is done in terms of alleviating poverty, adopting healthy behaviors, and nurturing the next generation.

Lastly, if you could visit anywhere in the world, where would that be and why?

Bhutan. I had a colleague that worked at the Hib Initiative who visited Bhutan. It is very difficult to go there, and you need to have a special reason to visit. My colleague went as a part of a vaccine delegation and she said the country is just pristine, the air is clean and clear, and you can hear birds chirping everywhere. I would love to see that country which has been unspoiled by modern life.