A key tool in the race against drug resistance: vaccines

January 22, 2019 by Katie Regan

Drug resistance is one of the biggest threats to global health today. Vaccines can help.

Male hospital pharmacist in Kenya looking at a binder of paperwork. Photo: PATH/Eric Becker.

What can we do when important drugs available in this Kenyan hospital pharmacy stop working? Photo: PATH/Eric Becker.

Imagine you’re sick. You have a high fever and are wracked with shuddering chills; your head is throbbing and you can’t stop vomiting. You manage to walk thirty minutes to the nearest clinic, and then comes the diagnosis: malaria. You’re frightened, because you know that in severe cases malaria can cause seizures and organ failure; it can lead to coma, and even to death. But you’re not that worried because there are drugs available to treat it. Your doctor writes you a prescription for an antimalarial and sends you home, your fear fading.

Now, imagine the antimalarial doesn’t work. That it can’t work, because the parasite you’ve contracted has developed a resistance to our most effective treatments.

It may sound dramatic, but it is a reality we’re already beginning to see. Antibiotics, antivirals, and other front-line drugs are imperative to curbing long-term illnesses and deaths caused by some of the world’s most infectious and communicable diseases. But organisms are adapting quickly and outwitting many current treatments. Growing drug resistance is one of the gravest problems facing the world today and we need to address it, now.

Vaccines can help. We’re looking forward to several vaccine advancements this year that have the potential to prevent increasingly costly and deadly diseases.

17486 Precious Namakau, community health worker, 38 years old, 3 children, wearing cap and glasses, test and treat apron, stands outside with the Mandia community health post's water tower in the background. Photo: PATH/Gabe Bienczycki.

Community health workers like Precious Namakau in Zambia are on the front line in the fight against malaria. But several key malaria prevention and treatment measures are starting to wane in efficacy. Photo: PATH/Gabe Bienczycki.

Malaria vaccines: new tools to fight a very old disease

Vaccines are a proven prevention tool that save millions of lives every year—and a powerful weapon in the fight against drug resistance. Vaccines help stem the spread of resistance by preventing people from getting sick in the first place, thereby limiting the need for these powerful drugs. We need effective vaccine solutions that can work in concert with existing interventions to both save lives and win the race against resistance.

Malaria is a prime example of this need. The disease kills 438,000 people annually—most of them, children in Africa. Infections and deaths due to malaria had been falling steadily but have plateaued in recent years. And now, several of the most effective prevention and treatment measures are starting to wane in efficacy. Disease-carrying mosquitoes, for instance, have demonstrated growing resistance to the insecticides used in bed nets and indoor spraying campaigns. Even more worrisome, some malaria-causing parasites spreading in Southeast Asia are resistant to the lifesaving medication artemisinin—and to other malaria drugs as well. Drug-resistant malaria threatens progress on controlling this disease and reducing the malaria burden. The biggest fear is that these superbugs could spread into India and then into the malaria strongholds of Africa.

PATH’s Malaria Vaccine Initiative is working to advance vaccines that can fight the disease—and one is ready for pilot introduction. RTS,S/AS01, developed by GSK—and in collaboration with PATH since 2001—will be rolled out starting this year to approximately 360,000 children annually in areas of Ghana, Malawi, and Kenya. This is an historic first step to possible wider use across Africa, where it could save thousands of lives in combination with current interventions.

But it’s not just about creating new vaccines—sometimes it’s about using the ones we already have.

Extending the reach of existing vaccines

Take typhoid: For most high-resource countries, typhoid is largely a memory, stamped out in the 1940s with the advent of antibiotics and improved sanitation. However, for the millions of people living in low- and middle-income countries, typhoid is a very present danger. A life-threatening enteric disease spread by contaminated food and water, typhoid disproportionately affects children in low resource countries, resulting in nearly 12 million cases globally every year.

And like malaria, drug resistance threatens to undo the progress we’ve made in the fight against typhoid.

Drug-resistant typhoid cases have increased at rapid pace in the last decade. Typhoid is typically treated with antibiotics but as resistant strains become more common, antibiotic treatment courses have become lengthy and more expensive. Not only are these treatments difficult on the patient, they are expensive and inflict long-lasting economic repercussions on families, communities, and countries. In many areas, the only remaining antibiotics that are able to threat resistant typhoid infections aren’t even available.

But unlike malaria, licensed vaccines against typhoid do already exist—the challenge is ensuring they’re accessible to the people who need them most. Previous generation typhoid vaccines posed several barriers to uptake, which meant the vaccines weren’t regularly used in the countries that suffered the highest burden. But, a new typhoid conjugate vaccine (TCV) that provides longer-lasting protection, requires fewer doses, and can be given to children as young as six months old are newly World Health Organization (WHO) prequalified and a recommended prevention solution. TCVs are safe, efficacious, and proven to prevent typhoid, therefore keeping children, families, and communities protected against potentially drug-resistant strains.

PATH, as part of the Typhoid Vaccine Acceleration Consortium, is working with stakeholders to support the first country introduction of TCVs into routine vaccination programs this year. We are working with the governments of typhoid-endemic countries to make the decision to introduce TCV. In light of ongoing extremely drug resistant cases of typhoid, PATH is supporting governments to seek Gavi funding for TCV introduction as part of an integrated solution (alongside improvements in water, sanitation, and hygiene) to prevent and control typhoid.

19220.jpeg Workers at the IVAC facility in Vietnam are working on a new flu vaccine. PATH/Matthew Dakin

Vietnam’s Institute of Vaccines and Medical Biologicals just achieved national licensure of a seasonal influenza vaccine, and expects to secure licensure of a pandemic influenza vaccine later this year. Photo: PATH/Matthew Dakin.

Newer vaccines that target the biggest threats

Advancements against malaria and typhoid are just some of the vaccine successes PATH is looking forward to this year.

Vietnam’s Institute of Vaccines and Medical Biologicals just secured national licensure for its seasonal trivalent inactivated influenza vaccine, and is poised to do the same later this year for its inactivated influenza A/H5N1 vaccine—helping to shore up the world’s defenses against seasonal and pandemic influenza. The next influenza pandemic is not a question of “if,” but “when”—and seasonal influenza vaccine production is the backbone of pandemic preparedness. By maintaining manufacturing capacity on an annual basis, producers are able to smoothly transition between products in the case of a pandemic. In a time when influenza viruses are showing increasing signs of resistance to antiviral drugs, we need as many manufacturers as possible equipped with the skills and capacity to produce these lifesaving vaccines.

A low-cost pneumococcal conjugate vaccine (PCV), produced by Serum Institute of India Pvt. Ltd. (SIIPL) and supported by PATH, is nearing the end of development and is targeting WHO prequalification, which could be possible in the next year. Pneumococcal disease kills hundreds of thousands of children each year worldwide (mostly in Africa and Asia) and is a leading cause of severe bacterial pneumonia, which has begun to show resistance to the first-line antibiotics used for treatment. Effective PCVs—which protect against some kinds of pneumococcus—already exist and save lives around the world, but their high cost means that many countries can’t afford them without substantial donor assistance. Or sometimes even at all. SIIPL’s vaccine is designed to protect children in low- and middle-income countries from the most common kinds of pneumococcus in Africa and Asia and at less than two-thirds the usual cost.

The Philippines will be introducing Japanese encephalitis vaccines in five high-risk regions. The vaccines will reach more than 2 million children under the age of five, protecting them from incurable disease that leaves up to half of all survivors with permanent neurological damage. There is no treatment for this virulent disease, so the availability of vaccines is the only way to prevent the infection. PATH has so far helped to introduce or expand the vaccine in ten countries outside of China (where it was developed), reaching nearly 300 million people throughout Southeast Asia and the Western Pacific.

A Phase 3 clinical study of a non-replicating rotavirus vaccine (NRRV) will start in Africa later this year—the first time any NRRV candidate has reached this stage of development. PATH is also playing a supportive role in the introduction of new India-made rotavirus vaccines in several low resource countries. Rotavirus is the most common cause of severe and fatal diarrhea in infants—the vast majority of whom live in resource-limited countries—and vaccines are the best way to prevent this incredibly resilient bug.

Drug resistance is an intimidating problem—but vaccines present a remarkable promise. The power to prevent disease rather than treat it can lessen our reliance on critically important drugs, ensuring they remain potent when we need them. PATH’s work on vaccine solutions is helping the global community in the race against resistance.

Vietnam Influenza Vaccine

Vietnam’s Institute of Vaccines and Medical Biologicals just achieved national licensure of its seasonal trivalent inactivated influenza vaccine, and is poised to secure the same later this year for its inactivated influenza A/H5N1. Photo: PATH.

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