Vaccines: A Top Priority for Global Health

By: Olivier Charmeil

Vaccines can easily become the “forgotten hero” for the enormous impact they have had on global health. When vaccines are successful, they prevent infectious diseases, many of which become forgotten over time. Mass vaccination programs have significantly improved global health and decreased mortality from vaccine-preventable diseases, such as smallpox, polio, pertussis and diphtheria. In high-income countries, lower respiratory infections are the only infectious diseases among the 10 leading causes of death. However, vaccine-preventable diseases remain prevalent and responsible for excessive mortality in poorer nations, particularly in children.[1]  According to the World Health Organization, as many as 2.5 million children may die of vaccine-preventable diseases in a single year.[2]

Since the inception of the WHO Expanded Program on Immunization (EPI) in 1974, much progress has been made in vaccinating children around the globe against infectious diseases. The Global Alliance for Vaccines and Immunization (GAVI) recognized vaccination as a collective activity and increased the global immunization effort. The Bill & Melinda Gates Foundation’s 2010 commitment to infuse $10 billion into immunizations during the next 10 years – Decade of Vaccines – has the potential to decrease morbidity and mortality from vaccine-preventable diseases to historical lows.

Formal Analyses of the Value of Vaccines

Estimates of cost-effectiveness and cost-benefits vary depending on the specific vaccine, the locale and the delivery strategy. In nearly every analysis, vaccines emerge as a cost-effective strategy in enhancing global health, although the payback is not always immediate. Over time vaccines prevent illness and disability, save lives, free funds that would be spent on treatment of vaccine-preventable diseases, and lead to a healthier, more productive society.

A recent study calculated the economic benefits of increasing childhood vaccination rates in 72 countries to 90 percent. The specific vaccines were those against pertussis, measles, rotavirus, malaria (assuming a vaccine is available by 2015), pneumococcal and Haemophilus influenzae type b (Hib) pneumonia, and meningitis. Over the next ten years the expanded vaccination effort would prevent 426 million cases of illness, save 6.4 million lives, and avoid $6.2 billion in treatment costs. Gains from increased productivity would total $145 billion.[3]

The cost of vaccines, especially the older ones, is a mere fraction of the cost of treating the illnesses they prevent. Estimated costs per fully immunized child (that is, a child who has received the six original EPI vaccines to protect against diphtheria, pertussis, tetanus, measles, polio and tuberculosis), range between $3 and $31, depending on the location and the vaccine strategy.[4] Of course, some newer vaccines, based on technologies unavailable 50 years ago, cannot be compared with older vaccines. The takeaway message here is that all vaccines avert treatment costs and save lives.[5] For example, the vaccine to protect against Hib costs about seven times as much as the six original EPI vaccines combined. But it is so effective in preventing serious, often fatal meningitis and pneumonia that 89 countries had offered it in their infant immunization programs by 2004.[6]

Far-Reaching Societal Benefits

Individuals, families and their communities reap additional advantages that cannot be directly converted into dollars or lives saved. These gains are particularly relevant for low-income countries, where the burden of vaccine-preventable diseases is greatest.

A vaccination encounter may represent a rare opportunity for some people to come into contact with health care providers. In the course of the immunization process, a treatable medical condition may be detected before it has caused irreparable damage; health education may be introduced and promoted.

Challenges to the Expansion of Vaccine Efforts

Countries that have achieved great gains in vaccination still have unvaccinated young residents. Many of these children live in remote areas, and reaching them will take a concerted effort. Not only is it more expensive to deliver vaccines to isolated areas, but it may require new strategies or vaccines. To illustrate, a vaccine that requires continual refrigeration poses a problem in places with unstable electricity. Replacing such a vaccine with a heat-stable alternative could facilitate access to vaccines and increase coverage rates.

Costs are a major challenge to expanded vaccine efforts. Factors to consider include delivery strategies, vaccine prices and the scale of a vaccination program. One analysis found that the most expensive component is labor.[7] Therefore, strategies that minimize labor, such as administration of combination vaccines, may control costs.

Public perception is another challenge to broader vaccine coverage. After some countries became complacent and ended their campaigns against polio, the disease began to resurface. Because of – often unfounded – concerns about vaccine safety, some parents refuse to give their children recommended vaccines.

 
A Few Troublesome Diseases

A brief look at three diseases – pneumonia, diarrhea caused by rotavirus, and dengue – illustrates the importance of expanded vaccination efforts. The first two diseases are the biggest killers of young children throughout the world, whereas dengue represents a disease that has crossed into new territory.

Pneumonia. About 1.6 million children younger than 5-years old worldwide every year from pneumonia, making it a greater killer than AIDS, malaria, and tuberculosis combined. Among children in this age group who die, pneumonia is the cause in 18 percent of cases.[8]

Vaccines are available to protect against the two most common bacterial causes of pneumonia, Streptococcus pneumoniae and Hib. These vaccines also protect against meningitis and other serious diseases caused by these infectious agents. Yet only 44 countries were using pneumococcal vaccines by the end of 2009.[9]

If more children around the world received vaccinations to prevent pneumonia in the next 10 years, the results would be phenomenal. One estimation is that more than 56 million cases and 2,661,000 deaths from pneumonia could be prevented.  This would free up nearly $68,000 million to spend for other purposes.[10]  According to another calculation,  the pneumococcal vaccine would still constitute a cost-effective intervention even at a cost of more than $26 a dose.[11]

Most industrialized countries routinely immunize children with the Hib vaccine, and as a result invasive disease has practically disappeared in many nations. But half of all infants live in countries that do not offer the vaccine in their routine immunization schedule, putting these children at risk for Hib pneumonia.[12]

Rotavirus diarrhea. Second only to pneumonia, diarrhea is responsible for 15 percent of deaths of children younger than 5.[13] Only 23 countries were using vaccines against rotavirus, a major cause of diarrheal disease in infants and young children, by the end of 2009.[14]

Persistence of rotavirus diarrhea in areas where water, sanitation, and personal hygiene have improved in recent years is proof that widespread vaccination also is essential to limit this disease. Because of the serious side effects of an early rotavirus vaccine, lingering, misplaced concern about safety may contribute to the minimal use of current, highly effective vaccines.

With an expanded global vaccination program over the next decade, 316,654,000 cases of rotavirus infection could be averted. A total of 1,525,000 deaths could be avoided if nearly every infant living in risk areas were vaccinated.[15]

Dengue. Once limited in scope to tropical urban areas, the mosquito-borne infection dengue has spread dramatically in recent decades: two-fifths of the world population is now at risk. While dengue fever is still primarily a tropical disease that occurs in cycles in south Asia and Central and South America, the dengue virus has dramatically increased its range over the past three decades.  In the 1950s, just nine countries reported outbreaks of dengue to the WHO. Today, more than 100 countries in Africa, the Americas, the Eastern Mediterranean and the Western Pacific are considered endemic regions, with Southeast Asia and the Western Pacific being most seriously affected.

Approximately 2.5 billion people are at risk for dengue infection in tropical and subtropical regions. The disease infects an estimated 50-100 million people annually, many of them children.[16] Dengue is characterized by high fever, severe muscle and joint pain, and rash. A serious form of the infection is called dengue hemorrhagic fever, which can be fatal in up to 10 to 15 percent of cases.[17]

There is no effective treatment for dengue.  Control has been the focus for many years, through environmental measures, including removal of standing water where mosquitoes breed and insecticide spraying. These measures, however, have failed to curtail the spread of dengue, pointing to the need for better preventive tactics.

Today, several vaccines are in various stages of advanced development, and preliminary data are encouraging. A balanced immune response was generated against all four subtypes of the dengue virus in a recent study among American adults using Sanofi Pasteur’s candidate vaccine. A large-scale clinical study using the Sanofi Pasteur vaccine candidate to assess efficacy in children has begun in Thailand, while other Phase 3 trials have also been initiated. If the Sanofi Pasteur trials are successful, dengue vaccine could be available as early as 2015-2016, providing a much needed public health intervention for this growing, worldwide threat. 

Conclusions

Vaccines are unquestionably a cost-effective preventive intervention, although the benefits may not be immediately apparent. Over time, vaccines save lives, avert long-term disabilities, and make treatment for associated illness unnecessary.

Expansion of programs to reach more children with more vaccines will require substantial resources for vaccine development and delivery. Consequently, it is imperative for the global community to deploy a consistent and coordinated approach for developing appropriate vaccination strategies for specific countries or regions. Key considerations include introduction of new vaccines, infrastructure for disease monitoring and surveillance supported by lab-based confirmation, and immunization strategies to cultivate innovative financing mechanisms for vaccine purchase and sustainable immunization programs.

We are on the verge of realizing a new era in vaccine innovation with enormous global public health potential. Our success hinges on the global community’s ability to spearhead new ways to address these issues and ensure a stronger appreciation for the vital role vaccines play in keeping deadly infectious diseases at bay.

REFERENCES

[1]  WHO. The top 10 causes of death. Available at: http://www.who.int/mediacentre/factsheets/fs310/en/index.html. Accessed July 15, 2011.

[2]  WHO. Challenges in global immunization and the Global Immunization Vision and Strategy 2006-2015. Weekly Epidemiol Rec 2006;81(19):190-195.

[3] Stack ML, Ozawa S, Bishai DM, Mirelman A, Tam Y, Niessen L, et al. Estimated economic benefits during the “decade of vaccines” include treatment savings, gains in labor productivity. Health Affairs 2011;30(6):1021-1028.
 
[4]  Brenzel L, Wolfson LJ, Fox-Rushby J, Miller M, Halsey NA. Vaccine-preventable diseases. In Disease Control Priorities in Developing Countries. 2nd ed. New York: Oxford University Press; 2006:389-411.

[5] Brenzel L, Wolfson LJ, Fox-Rushby J, Miller M, Halsey NA. Vaccine-preventable diseases. In Disease Control Priorities in Developing Countries. 2nd ed. New York: Oxford University Press; 2006:389-411.

[6] WHO. Haemophilus influenza type B (HiB). Available at http://www.who.int/mediacentre/factsheets/fs294/en/#.

[7] Brenzel L, Wolfson LJ, Fox-Rushby J, Miller M, Halsey NA. Vaccine-preventable diseases. In Disease Control Priorities in Developing Countries. 2nd ed. New York: Oxford University Press; 2006: 389-411.
 
[8] WHO. Pneumonia. Available at: http://www.who.int.mediacentre/factsheets/fs331/en/index.html. Accessed July 25, 2011.

[9] WHO. Immunization highlights: 2010. Available at: http://www.who.int/immunization/newsroom/highlights/2010/en/index1.html. Accessed July 26, 2011.

[10] Stack ML, Ozawa S, Bishai DM, Mirelman A, Tam Y, Niessen L, et al. Estimated economic benefits during the “decade of vaccines” include treatment savings, gains in labor productivity. Health Affairs 2011;30(6):1021-1028.
 
[11] Vespa G, Constenla DO, Pepe C, Safadi MA, Berezin E, Cassio de Moraes J, et al. Estimating the cost-effectiveness of pneumococcal conjugate vaccination in Brazil. Pan Am J Public Health 2009;26(6):518-528.

[12] WHO. Invasive Haemophilus influenzae type B (Hib) disease prevention. Available at: http://www.who.int/nuvi/hib/en/index.html. Accessed July 26, 2011.

[13] WHO. World Health Statistics 2011. Available at: http://www.who.int/whosis/whostat/2011/en/index.html. Accessed July 15, 2011.

[14]  WHO. Immunization highlights: 2010. Available at: http://www.who.int/immunization/newsroom/highlights/2010/en/index1.html. Accessed July 26, 2011.
 
[15] Stack ML, Ozawa S, Bishai DM, Mirelman A, Tam Y, Niessen L, et al. Estimated economic benefits during the “decade of vaccines” include treatment savings, gains in labor productivity. Health Affairs 2011;30(6):1021-1028.

[16] WHO. Dengue and dengue haemorrhagic fever. Available at: http://www.who.int/mediacentre/factsheets/fs117/en/index.html. Accessed July 27, 2011.
 
[17] Beatty M, Letson GW, Margolis HS. Estimating the global burden of dengue. Am J Trop Med Hygiene 2009;81(5):231.

Olivier Charmeil is president and CEO of Sanofi Pasteur.