JAMA Forum: Tackling the Ebola Epidemic

Lawrence Gostin, JD

Lawrence Gostin, JD

The Ebola virus epidemic in West Africa is now out of control, but it shouldn’t have come to this. Ebola virus disease (EVD) is a preventable disease, but the current epidemic is challenging efforts to contain it. Previous outbreaks that have occurred since the virus was first detected in 1976 have been confined to rural areas. This time, EVD has reached the urban landscape, with people and animals congregating together. Extensive travel across land borders and by air is furthering its spread.

Why Ebola Is Out of Control

The most affected countries—Guinea, Liberia, and Sierra Leone (with recent spread to Nigeria, which currently has a dozen cases)—are ranked lowest in global development and do not have the basic infrastructure to contain the Ebola epidemic. Even with international help, it will take at least 6 months to bring the crisis under control, according to Médecins Sans Frontières/Doctors Without Borders. For now, Ebola is spreading unchecked because of such factors as fragile health systems in resource-poor countries, cultural practices, and deep-seated distrust.

Broken Health Systems

Being treated or working in a hospital in affected states is hazardous. Health professionals are the most susceptible: they typically care for infected patients without personal protective equipment and infection controls; they lack training in differential diagnosis of and treatment for EVD; and they are underpaid. Patients, too, perceive that hospitals in the affected countries are unsafe places that offer little effective treatment. Consequently, patients with Ebola-type symptoms stay away, and those who need treatment for myriad health problems—from AIDS and malaria to cancer and heart disease—remain untreated in the community.

The persistence of traditional burial and other cultural practices in West Africa also make it more difficult to contain Ebola. Loved ones come in close contact with the deceased, including ritual touching and bathing. Burial practices create the conditions for transmitting EVD, which then can be spread throughout the community. Another practice, consuming bush meat, which might include animals that are reservoirs for Ebola virus, is a traditional source of food, especially for poor Africans, providing life-sustaining protein. Women, as the traditional caregivers, are more likely to contract the virus than men.

Further challenging attempts to contain the spread of Ebola are common misperceptions, such as the belief that aid workers from medical groups were spreading the disease. Public education has been neglected and governments have curtailed accurate news reporting about the crisis. Epidemic control requires trust and an informed public, so risk communication is fundamental to controlling Ebola’s spread.

Ethical Issues

Also related to the issue of trust has been the use of scarce experimental therapies. More than 20 Ebola outbreaks have erupted in sub-Saharan Africa, yet the world was unprepared for the current tragedy, with no licensed vaccines or treatments. (This lack of readiness would not have surprised Albert Camus. As he wrote in The Plague, “Everybody knows that pestilences have a way of recurring in the world; yet somehow we find it hard to believe in ones that crash down on our heads.”)

An experimental drug called ZMapp, which has neither been proven effective nor tested for safety in humans, was available in scarce amounts and was administered to 2 US aid workers and, reportedly, to a Spanish priest. The last remaining doses have now been delivered to West Africa, but the initial perceived preference given to white foreign workers fueled a sense of injustice. Although selecting who should get the untested treatment is an agonizing choice, it’s my opinion that priority should be given to African health workers, who die of Ebola in far greater numbers than do foreign workers. In any case, it is vital that allocation decisions be made fairly and transparently. The decision to treat the foreign workers was made behind closed doors without community consultation. Going forward, high-resource countries should create public-private partnerships to ramp up development and rigorous evaluation of vaccines and treatments.

Militarization of a Disease

Adding to the distrust that hinders attempts to control the epidemic is local populations’ fear not only of Ebola but also of the militarization of the disease. Countries have erected cordons sanitaires (guarded lines preventing anyone from leaving), but are using ancient methods to enforce the quarantine. In West African hot spots, armed troops have established blockades, closed roads, and banned travel beyond the guarded perimeter.

As a result, the populace is finding it hard to obtain food and other basic necessities. Targeted travel restrictions may be necessary, but there is a smarter way to go about them, through humane care and incentives. Governments should provide people with nourishing food, health care, and psychosocial support. Transmission hot zones can’t be ignored, but neither can the needs and human rights of communities.

What Can Be Done Now? A “Health Systems Fund”

Fragile health systems are at the root of the problem, and bolstering them is a key to fighting Ebola and preventing another uncontrolled outbreak. Affected countries are unprepared for Ebola’s complexities; they are unable to provide all their people basic health services, much less the requirements of an Ebola response, including full body protective gear, specially trained health workers, isolation units, and advanced laboratory capacity with higher biosafety capabilities. Building strong health systems would rebuild the most basic community asset: trust. Looking ahead, the international community should mobilize to provide sustainable funding scalable to needs.

This crisis represents a manifest failing of the international community, particularly its wealthier members, which ought to have been generous in supporting surveillance and response capacities obligatory under the International Health Regulations (IHR). The World Health Organization (WHO), the World Bank, and the United States Agency for International Development, among others, have made notable pledges of support. But what the region needs now is an assurance that these funds will be ample and sustainable.

To address this need, I propose an emergency, and then an enduring, “Health Systems Fund” administered by WHO (with participation of local governments and civil society) and supported by high-resource countries. Considering the funding needs, an immediate (emergency) down payment of $200 million is needed for the affected countries and their at-risk neighbors. The money should be spent to strengthen health systems. Building on recent pledges of support, these additional funds could reward and motivate frontline health workers, ensure humane conditions in communities subjected to cordon sanitaire, and establish surveillance and response preparedness.

This fund would be surprisingly affordable, with this initial installment of funding representing only 1% of international health assistance. Growing the fund over time into a multibillion dollar funding channel for lower-income countries would finally make it possible to mobilize the resources envisioned in the IHR, as well as the growing global commitments to universal health coverage. Eventually, the fund might be merged with the Global Fund to Fight AIDS, Tuberculosis and Malaria into a new Global Fund for Health.

It is in all states’ interests to contain health hazards that may eventually travel to their shores. But beyond self-interest are the imperatives of health and social justice: a humanitarian response that would actually work, now and for the long term.

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About the author: Lawrence O. Gostin, JD, is University Professor and Faculty Director, O’Neill Institute for National and Global Health Law, Georgetown University Law Center, and Director of the World Health Organization Collaborating Center on Public Health Law and Human Rights. His most recent book is Global Health Law (Harvard University Press).

About The JAMA Forum: JAMA has assembled a team of leading scholars, including health economists, health policy experts, and legal scholars, to provide expert commentary and insight into news that involves the intersection of health policy and politics, economics, and the law. Each JAMA Forum entry expresses the opinions of the author but does not necessarily reflect the views or opinions of JAMA, the editorial staff, or the American Medical Association. More information is available here and here.

 

 

After Chikungunya Virus Transmission Detected in United States, Health Authorities Brace for Wider Spread

US public health authorities are targeting the mosquitos, like this female Aedes aegypti, that spread chikungunya, a virus that causes severe joint pain. Image: CDC/James Gathany

US public health authorities are targeting the mosquitos, like this female Aedes aegypti, that spread chikungunya, a virus that causes severe joint pain. Image: CDC/James Gathany

The chikungunya virus has officially arrived in the United States. On July 17, public health authorities confirmed the first 2 cases of local transmission of the virus in the United States in Florida.

An abrupt onset of a fever higher than 102°F and severe pain or swelling in multiple joints are hallmarks of chikungunya infection, said Anna M. Likos, MD, MPH, state epidemiologist and director of the division of disease control and health protection at the Florida Department of Health. Patients may also develop a rash, muscle pain, or headache, according to the US Centers for Disease Control and Prevention (CDC). On average, symptoms appear 3 to 5 days after exposure but can occur 1 to 12 days after exposure.

The spread of chikungunya virus within the continental United States was not unexpected, said health authorities. On December 2013, the World Health Organization reported the first local transmission of chikungunya virus in the Western Hemisphere, in the Caribbean. Within months, the disease spread through much of the Caribbean and Central and South America.

Reflecting this spread, the number of US travelers who became infected with the virus during travel to affected regions also has rapidly climbed, with 234 as of July 15, according to the CDC.

The species of mosquitoes that spread the virus, Aedes aegypti and Aedes albopictus, live in the southeastern United States and parts of the Southwest, and A albopictus can also be found in the Mid-Atlantic states and lower Midwest. Amy Vittor, MD, PhD, an infectious disease physician at the University of Florida, noted that the currently circulating strain of chikungunya in the Americas is spread more easily by A aegypti, which is less common in the United States than A albopictus.

However, chikungunya is unlikely to spread as extensively in the continental United States as it has in the Caribbean and other parts of the Americas. J. Erin Staples, MD, PhD, medical epidemiologist with the CDC’s division of vector-borne diseases in Fort Collins, Colorado, noted that US individuals spend far less time outside and typically have air conditioning and door and window screens.

The spread of chikungunya infection in the United States will likely be similar to the spread of dengue virus, which is transmitted by the same mosquitoes. Staples noted that during 2013 there were about 2.4 million cases of dengue reported in the Caribbean and Central and South America, 773 travel-related cases in the United States, and 48 cases of local transmission in the continental United States. However, in contrast to dengue, for which many infections are mild or asymptomatic, an estimated 80% of people infected with chikungunya will likely develop symptomatic disease. Most recover, but some have lasting joint pain.

During the last large-scale chikungunya outbreak in 2006 in Africa and Southeast Asia, a single mutation caused a change in the virus that allowed A albopictus to spread it more efficiently. Vittor explained that if a similar mutation occurs in the currently circulating strain, the United States will be at greater risk of local transmission.

“It will be a game changer,” she said.

Public health officials in Florida are working to quickly curb spread of the virus. The department has reached out to public health directors and physicians throughout the state and is trying to identify every travel-associated and locally transmitted chikungunya case. Once a case has been identified, the department works with local mosquito control agencies to prevent local transmission by stepping up mosquito abatement efforts.

“We are taking steps to ensure we are finding every case,” said Likos.

The Florida Department of Health recommends that individuals living in or visiting areas where chikungunya infection is spreading take steps to prevent mosquito bites throughout the day (because the mosquitoes that carry the virus are active and bite during the day), by using insect repellent, wearing long sleeves, and making sure window and door screens are intact and closed. The department also recommends that Floridians be careful to remove standing water from boat covers, pots, and other places water collects to eliminate potential breeding sites for chikungunya’s mosquito vectors.

Updated information about chikungunya is available on the CDC’s website.

Inexpensive Lifesaving Therapy for Diarrheal Illness in African Children Is Underused by For-Profit Clinics

Neeraj Sood, PhD, of the University of Southern California, and Zachary Wagner, a doctoral student at University of California, Berkeley, found that for-profit health facilities in sub-Saharan Africa are less likely than large public hospitals to provide lifesaving rehydration to children with diarrhea. Image: University of Southern California

Neeraj Sood, PhD, of the University of Southern California, and Zachary Wagner, a doctoral student at University of California, Berkeley, found that for-profit health facilities in sub-Saharan Africa are less likely than large public hospitals to provide lifesaving rehydration to children with diarrhea. Image: University of Southern California

Although oral rehydration can mean the difference between life and death for children with diarrheal illnesses in sub-Saharan Africa, a new study suggests that for-profit clinics may be more likely than large public hospitals to prescribe expensive treatments instead.

Children younger than 5 years are at risk of death from diarrheal illnesses, which claim about 700 000 young lives each year. Most of the deaths result from dehydration and can be prevented by providing a solution of glucose and electrolytes. This simple and inexpensive intervention, which can cost less than 50 cents, is referred to as oral rehydration therapy (ORT). Unfortunately, this lifesaving tool is underused in sub-Saharan Africa.

To better understand why some children aren’t receiving ORT, Neeraj Sood, PhD, of the University of Southern California, and Zachary Wagner, of the University of California,Berkeley, analyzed survey data on 19 059 children from 29 countries in sub-Saharan Africa collected between 2003 and 2011. When they compared the care children with diarrhea received from for-profit vs public health providers, they found that for-profit providers were 15 percentage points less likely to provide ORT and about 12 percentage points more likely to provide treatments like antibiotics that may not be necessary and may cost more.

The for-profit facilities tended to be single-practitioner clinics or pharmacies compared with large public hospitals. The researchers found that pharmacies “were particularly likely to provide poor care.” Although wealthy parents were more likely to visit for-profit providers, underprivileged children from rural areas were disproportionately likely to receive poor care at for-profit facilities.

These findings are particularly concerning because for-profit facilities are becoming more common in sub-Saharan Africa as public health systems struggle to meet demand for care. Alan Magill, MD, president of the American Society of Tropical Medicine and Hygiene, said in a statement that the data suggest better coordination with the emerging private care sector in this region is needed to ensure the dissemination of evidence-based care.

“Given the important role that private health care providers are playing in Africa, this research shows that we need to be employing engagement strategies that we know have been successful in helping combat other diseases like HIV and malaria,” Magill said. “It is an illustration of the hand-in-hand relationship that research plays with clinical care.”

Despite Economic Growth, Childhood Malnutrition Not Improving in Developing Nations

Increasing GDPs in developing nations not associated with improved childhood nutrition. Image: iStock.com/MShep2

Rising GDPs in developing nations not associated with improved childhood nutrition. Image: iStock.com/MShep2

Poor childhood nutritional status contributes to childhood mortality, one of the key global indicators of poverty. It might naturally follow, then, that improving the economic situation of developing nations should lead to improvements in childhood malnutrition, but this may not be the case.

study released yesterday in The Lancet Global Health, the largest to date to examine this issue, looks at data collected from 1990 to 2011 in 36 low- and middle-income countries around the world, including India, Colombia, Nigeria, and many other sub-Saharan African nations, and suggests that increases in per-head gross domestic product (GDP) over these 2 decades have generally not been associated with improvements in childhood nutritional status.

Researchers at the Harvard School of Public Health quantified childhood nutritional status based on data from the Demographic and Health Surveys, a standardized, randomly administered set of surveys conducted by ICF International in developing nations worldwide. The researchers focused on 3 measures in children aged 0 to 35 months—height, weight, and height-for-weight—and compared these measures to World Health Organization reference values; very low measurements represented stunting, underweight, and wasting, respectively. Using standardized GDP data from the Penn World Tables, they then compared trends in each country’s change in GDP vs rates of childhood stunting, underweight, and wasting over time.

For the entire sample representing nearly half a million children over the entire period, 35.6% of children were stunted, 22.7% were underweight, and 12.8% were wasted. For most (but not all) countries, per-head GDP increased over time, and rates of stunting, underweight, and wasting generally decreased. However, the magnitude of this decrease was very small: for every 5% increase in per-head GDP, there was, on average, a 0.4% decrease in the odds of being stunted, a 1.1% decrease in the odds of being underweight, and a 1.7% decrease in the odds of being wasted. Even though these numbers were statistically significant (with narrow confidence intervals) due to the large sample size, from a public health perspective, they represent a “quantitatively very small to null association” that “challenges the assumption that economic growth will automatically lead to reductions in child undernutrition.”

The authors offer several possible explanations. First, economic growth might be unequally distributed within society, so that the poorest households, which are most likely to have malnourished children, may not be receiving any additional income. Second, even if poor households are receiving more income, it might not be spent in ways that enhance nutritional status—for example, the extra money might be spent mostly on non-food items. Third, rising household incomes might not be accompanied by the necessary public services and societal infrastructure to improve childhood nutritional status, such as universal vaccinations and appropriate prenatal and postnatal care. The authors state that these results “emphasize the need to focus on direct investments in health and nutrition and not to rely on the so-called trickle-down approach … to improve nutrition in children.”

Malnutrition May Interfere With HIV Treatment in Pregnant and Breastfeeding Women

   To protect child health, public health authorities in Uganda must combat both malnutrition and mother-to-child transmission of HIV.  Image: JAMA, ©AMA

To protect child health, public health authorities in Uganda must combat both malnutrition and mother-to-child transmission of HIV. Image: JAMA, ©AMA

Malnutrition may reduce levels of human immunodeficiency virus (HIV) medications in pregnant or breastfeeding women, which may hamper efforts to prevent mother-to-child transmission, according to a study published today in the The Journal of Clinical Pharmacology.

Maternal infections with HIV in sub-Saharan Africa present a pressing public health concern, with as many as 40% of pregnant women infected, according to the study authors. Antiretroviral treatment during pregnancy and breastfeeding can substantially reduce the risk that these mothers will pass the virus to their newborns, so many governments and aid organizations have emphasized maternal treatment as a way to curb transmission. The new findings bolster previous evidence demonstrating the importance of addressing malnutrition simultaneously with drug treatment.

Imke H. Bartelink, PharmD, of the University of California, San Francisco, and colleagues from the United States and Uganda found that malnutrition may complicate efforts to reduce mother-to-child transmission through antiretroviral treatment. The study involved 225 Ugandan women who were being treated for HIV infection. Many were malnourished; 80% reported lacking adequate food for their families, 50% reported moderate to severe hunger, and 26% lost weight during pregnancy.

The researchers analyzed blood spots and hair samples from the women for lopinavir, ritonavir, and efavirenz levels. They found that drug levels were substantially reduced in malnourished study participants compared with well-nourished participants, with a decrease in exposure of 33% for lopinavir, 15% for efavirenz, and 17% for ritonavir. As expected, they also found that during pregnancy the body clears lopinavir and ritonavir more quickly, something that clinicians account for when dosing pregnant women.

Previous studies also have suggested that malnutrition may reduce the likelihood that patients taking antiretroviral medication will take them as prescribed, without skipping doses. Bartelink and colleagues used the samples as a means to verify whether the adherence rates that patients reported were accurate, and confirmed that such testing can be a useful tool in helping to verify adherence.

Demonstration Projects Show Global Health Security Begins at the Local Level

A detection team of men in a remote village in Uganda prepare to assess an individual whose recent death may have been caused by the Ebola virus. Such on-the-ground detection teams are key elements in global health security. (Image: Justin Williams/Centers for Disease Control and Prevention)

A detection team in a remote village in Uganda prepare to assess an individual whose recent death may have been caused by the Ebola virus. Such on-the-ground detection teams are key elements in global health security. (Image: Justin Williams/Centers for Disease Control and Prevention)

Infectious disease threats know no borders, especially in a world where a potentially deadly infectious disease is only a 24-hour plane flight from anywhere in the world. So it’s not surprising that nations are increasingly recognizing the need for global health security, for strengthening local capacity to prevent, detect, and respond to public health threats that have global implications.

Such a challenge is an ambitious one, especially for developing countries without a strong public health infrastructure. To help develop an approach for achieving this goal, the US Centers for Disease Control and Prevention (CDC), partnered with the ministries of health in Vietnam and Uganda, conducted demonstration projects in 2013 in those countries. Findings from these projects, appearing today in the CDC’s Morbidity and Mortality Weekly Report, may help provide templates that other nations can use to both enhance their own health and contribute to global health security.

Addressing Global Health Threats

These efforts could also help nations keep their promises to meet core surveillance and response requirements of the International Health Regulations, which in 2005 were revised by the World Health Organization (WHO) in response to the need to address existing, new, and reemerging infectious diseases and other health threats, including chemical, biological, or radiological public health emergencies. The regulations, which are binding on 194 countries (including all WHO member states), are geared toward ensuring rapid gathering of information about a possible health threat, fostering an understanding of what may constitute a public health emergency of international concern, and making international assistance available.

The countries that signed on to the International Health Regulations had until June 2012 to meet the core surveillance and response requirements, but more than 80% of them failed to meet this deadline and have been given a 2-year extension.

CDC Director Thomas R. Frieden, MD, MPH, said he hopes countries can learn from the demonstration projects and implement effective measures to meet the regulations’ requirements. Doing so should help manage disease outbreaks within countries and prevent or minimize their spread to other countries, he said.

“We have unprecedented opportunity,” Frieden said, in the form of better technology for rapid detection and response and effective communication tools to report cases, such as social media and texting. “We have a different world now than we had just a few years back.”

In Vietnam, the CDC, Vietnam’s ministry of health, and certain international organization personnel launched a demonstration project from March 2013 to September 2013 to improve the country’s capacity to detect and respond to public health emergencies. The project team, which focused on establishing an emergency operations center that would receive, evaluate, and distribute information and coordinate response operations to a disease outbreak, demonstrated that early detection of and response to diseases and outbreaks could be made through this and other enhancements to the country’s health system, such as improving laboratory operations by increasing the capacity of diagnostic and specimen referral networks.

Michelle McConnell, MD, country director, CDC Vietnam, said enhancing information systems proved to be the most difficult challenge. “This system, by definition, encompassed many different institutions and levels of the public health system from the national to the provincial and district levels of the public health system,” McConnell said in an e-mail exchange. “Intra- and interdepartmental coordination and communication are critical to global health security, but also one of the greatest challenges.”

McConnell added that it is challenging for developing countries to focus on global health security because of economic constraints and other health priorities, but that Vietnam made it a priority. “The Vietnam ministry of health is very aware of the importance and priority of global health security and led with the highest level of commitment,” McConnell wrote. “Vietnam was one of the first nations in Asia to stop having new cases of SARS during that epidemic and, more recently, has stepped up efforts to prevent, detect, and respond to outbreaks of novel influenza viruses, such as H7N9.”

Mock Outbreaks and Preparedness

The demonstration project in Uganda focused on similar priorities: strengthening the public health laboratory system by increasing the capacity of diagnostic and specimen referral networks, enhancing existing communications and information systems for outbreak responses, developing an emergency operations center to serve as the focal point for communication, and assessing information emerging from the front lines of response to outbreak threats. To simulate the challenges Ugandan public health workers might encounter in reality, the project created mock outbreaks of multidrug-resistant tuberculosis, cholera, and viral hemorrhagic fever.

At the end of the project, 14 of 16 sites demonstrated they had improved in disease recognition, communication, and specimen transport. Laboratories showed an average 14% improvement from the baseline assessment.

“The exercise emphasized the importance of preparedness activities in the steps of preparedness, response, and recovery,” said Jeff Borchert, MSEH, from the CDC’s Office of Infectious Disease, who worked in Uganda on the project, in an e-mail exchange. “Next steps could include increased focus on preparedness planning in addition to the response aspect so that plans and supplies are in place ahead of any incident that might occur.”

In addition to demonstration projects, the CDC is also working in other areas to improve global health security. “CDC has been working with ministries of health around the world in a variety of public health activities, such as training epidemiologists to have core capacities to monitor infectious and noninfectious agents,” said Jordan W. Tappero, MD, MPH, director of CDC’s division of global health protection, Center for Global Health. “We really need to improve our surveillance capacity, the ability to track an event if it happens. Most countries have some way of tracking infectious disease, but those that don’t need to get it.”

Such improvements benefit individual countries as well as the global community, Frieden said. “What’s encouraging is when we do this in a country, it doesn’t just make that country safer from a particular threat; it improves the country’s ability to meet any health threat,” he said. “That ability is transferable.”

Even a Single Dose of the HPV Vaccine May Offer Lasting Protection

Mahboobeh Safaeian, PhD, of the National Cancer Institute, and her colleagues found that even a single dose of human papillomavirus vaccine can induce a lasting response. Image: National Cancer Institute.

Mahboobeh Safaeian, PhD, of the National Cancer Institute, and her colleagues found that even a single dose of human papillomavirus vaccine can induce a lasting response. Image: National Cancer Institute.

Just a single dose of a 3-dose vaccine against 2 strains of the human papillomavirus (HPV) may protect a woman for years, according to surprising results from a clinical trial in Costa Rica. The findings raise the possibility that fewer doses may be a feasible approach to protecting women, particularly in the developing world where costs and logistics can make multidose vaccinations hard for women to complete.

The vaccine is an important public health tool to protect women against infection with strains of the virus that may lead to cervical cancer. But the cost and the need for 3 doses of the vaccine have contributed to poor uptake of the vaccination in the United States. These barriers to vaccination are greater in the developing world, where women may be even more sensitive to costs or may face logistical challenges to getting repeated doses. With less access to screening and treatment for cervical cancer, women in the developing world are more at risk of death from cervical cancer, which is the most common cause of cancer-related death among women in the developing world.

But the findings by Mahboobeh Safaeian, PhD, an investigator at the National Cancer Institute, and her colleagues offer preliminary evidence that a less arduous HPV vaccination regimen may be possible. The researchers analyzed the HPV-16– and HPV-18–specific antibody levels in women who had received 1 dose of the HPV-16/18 vaccine (78 women), 2 doses one month apart (140 women), 2 doses 6 months apart (52), or 3 doses (120 women) over 4 years*. They also analyzed antibody levels in blood samples from 113 women who tested positive for HPV infection at enrollment. All of the vaccinated women remained seropositive for HPV-16/18 at 4 years after vaccination, with the group that received 2 doses 6 months apart having levels comparable with the 3-dose group. Even the 1-dose group had antibody levels to HPV-16 and HPV-18 that were 9 and 5 times higher, respectively, than women who were infected at enrollment, and the 2-dose group had antibody levels 24 and 14 times higher, respectively, than those who were presumably infected naturally. The antibody levels in the 1-dose group stayed steady from 6 months to 4 years after vaccination.

Further studies will be necessary to confirm the findings and prove that the 1-dose antibody levels are sufficient to protect against cervical cancer. In the meantime, however, the findings may have important implications for vaccine developers. Safaeian and her colleagues noted that the durable antibody response they documented is more similar to the response to a live-attenuated vaccine rather than a protein-based vaccine, which requires frequent boosting.

“Our findings challenge previous dogma that protein subunit vaccines require multiple doses to generate long-lived responses,” Safaeian said in a statement.

*This blog has been updated to include information omitted in the original draft.