Salk or Sabin? Using Both Polio Vaccines is Best, Study Reports

New research shows that the inactivated, injectable polio vaccine boosts mucosal immunity, making it an ideal tool to use with the oral vaccine to end poliovirus transmission. (Image: ©iStock.com/dina2001)

New research shows that the inactivated, injectable polio vaccine boosts mucosal immunity, making it an ideal tool to use with the oral vaccine to end poliovirus transmission. (Image: ©iStock.com/dina2001)

New research appears to have resolved a polio vaccine debate raging for more than 50 years: Is it more appropriate to use the oral, attenuated vaccine developed by Albert Sabin, MD, or the inactivated, injectable vaccine that Jonas Salk, MD, introduced?

The answer, based on a study published online today in Science, is that using both is best.

“This study has really revolutionized our understanding of inactivated polio vaccine and how it can fit within the global eradication program to help get this finished as quickly as possible,” coauthor Bruce Aylward, MD, MPH, the World Health Organization’s (WHO) assistant director-general of polio, emergencies and country collaboration, said during a press briefing.

Sabin’s oral formulation became the vaccine of choice in global eradication efforts because it induces superior mucosal immunity, is easy to administer, and costs less. Local immunity at mucosal surfaces such as those lining the gastrointestinal, respiratory, and urogenital tracts is important because they’re major entryways for viruses and other pathogens to enter the body.

However, the oral vaccine also has drawbacks. Mucosal immunity wanes over time, so multiple doses are necessary. Revaccination can be difficult or impossible in conflict zones such as Afghanistan, Nigeria, and Pakistan, where poliovirus remains endemic.

Also, the virus used to make the oral vaccine is weakened but still alive. It can be shed in feces, which increases local, national, and international transmission risks. On very rare occasions it can cause polio in the person who is vaccinated.

Scientists already knew that the inactivated vaccine prevented paralytic polio disease by spurring antibody production. But they weren’t certain about its role in mucosal immunity. So an international research team led by Hamid Jafari, MD, director for polio operations and research at WHO, enrolled nearly 1000 children in a clinical study to determine whether the inactivated vaccine boosts mucosal immunity. The trial took place in the Uttar Pradesh state of northern India, a longtime stronghold for the virus.

Children in the trial already had received multiple doses of oral vaccine as part of immunization programs. For the trial, they randomly received 1 dose of inactivated or oral vaccine, or no vaccine. Four weeks later, all the children received a 1-dose challenge with oral vaccine. At 3 follow-up periods during the next 2 weeks, the investigators measured poliovirus excretion in their stool—a sign of being infectious.

Compared with the control group, children who received the inactivated vaccine excreted anywhere from 39% to 76% less virus in their stool, depending on poliovirus type and children’s age. Older children excreted more virus than younger children. Only the older children who received oral vaccine excreted significantly less virus than controls.

“Giving inactivated polio vaccine makes people very, very less infectious,” Jafari said during the press briefing.

Since 1988, global eradication efforts have reduced polio cases by 99%. But Jafari said that effort now is at a crossroads. Endemic polio is confined to unstable regions that often are inaccessible to outsiders. “Yet the virus in these areas persists with incredible tenacity and threatens the increasingly vulnerable populations in polio-free countries with a weak or conflict-affected health system,” he noted.

“Inactivated polio vaccine will be a powerful additional tool in our arsenal to fight this disease in these remaining areas,” Aylward added.

The Global Polio Eradication Initiative’s strategic “endgame” plan calls for the introduction of inactivated polio vaccine by the end of 2015 in countries now using only the oral vaccine. “Both vaccines complement one another and should be used to interrupt the final chains of transmission to obtain a polio-free world in the most rapid and effective way possible,” coauthor Roland Sutter, MD, the WHO’s coordinator for research and product development, polio operations and research, said during the briefing.

 

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.

 ***

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.

 

 

Guideline: Patients With Liver Disease Should Be First in Line for New Hepatitis C Treatments

Patients with chronic hepatitis C virus infection who have severe liver disease should be among those first in line for an expensive new medication, according to a new guideline. (Image: JAMA, ©AMA)

Patients with chronic hepatitis C virus infection who have severe liver disease should be among those first in line for an expensive new medication, according to a new guideline. (Image: JAMA, ©AMA)

Patients with advanced liver disease or other severe symptoms of hepatitis C virus (HCV) infection should be first in line for an expensive new medication for the infection, according to a new guideline. The guideline, from the American Association for the Study of Liver Diseases and the Infectious Diseases Society of America, was created with support from the International Antiviral Society–USA (IAS-USA).

An estimated 3 million to 4 million US individuals have chronic hepatitis C infection and many of them remain undiagnosed. The infection may remain symptomless for years, but in individuals for whom the infection does eventually progress, severe liver disease or liver cancer may develop, and some will require liver transplantation. Potentially curative drugs have been available for years, but these therapies don’t work for everyone, require months of treatment, and often have onerous adverse effects.

The emergence of a new treatment for HCV infection, sofosbuvir, has been described as both a major step forward in treating the infection and a potential threat to the viability of the US health care system. The drug, which is sold under the trade name Sovaldi, can cure chronic HCV infections in a shorter time frame than older medications and is believed to have fewer adverse effects. However, its price tag of $1000 a pill—about $80 000 over the course of treatment—has been the focus of intense debate. As discussed in a New York Times blog post, the drug’s cost may drive up health insurance premiums and put a strain on state Medicaid budgets.

The new guidelines sidestep the drug’s costs and focus only on which patients are most likely to benefit from the drug. According to the new guidance, all patients with chronic HCV infection may benefit from treatment. But patients with severe liver scarring or liver disease, patients who have undergone an HCV-related liver transplant, and those with severe nonliver symptoms of chronic HCV infection should be first in line for treatment.

“We are most concerned about those with severe liver disease,” said Donald Jensen, MD, Director of the Center for Liver Diseases at the University of Chicago, during a press briefing. “Those with less severe disease also may benefit, but those without symptoms may be able to wait for better treatments to emerge,” explained Jensen, who co-chaired the panel that wrote the new guidance.

Jensen explained that 30% of patients with chronic HCV infections never progress to symptomatic disease and others may not develop symptoms for years. He noted for these individuals, it may be advantageous to wait until better therapies become available because there are other drug candidates in the pipeline.

Jensen said the organizations that developed the guidance chose to focus on prioritizing which patients are most likely to benefit from the new drug. But he also acknowledged that it would be impossible to treat all patients who are infected with HCV, because there simply are not enough clinicians with the necessary training to meet the demand.

But other panel members during the press conference acknowledged that costs are “the elephant in the room” that also make prioritization necessary.

“We understand the system is struggling because the medication is expensive and we need to give some prioritization,” said Michael Saag, MD, of the University of Alabama at Birmingham and a co-chair of the panel, representing IAS-USA.

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.

More Flu Patients Get Antibiotics Than Antivirals, Study Reports

Antiviral medications such as oseltamivir are too infrequently prescribed for patients with the flu, according to a new study. (Image: ©iStock.com/czardases)

Antiviral medications such as oseltamivir are too infrequently prescribed for patients with the flu, according to a new study. (Image: ©iStock.com/czardases)

Prescriptions for antibiotics outpaced those for antiviral medications by 2 to 1 among patients with confirmed influenza at several care centers during the 2012-2013 flu season, according to a new study.

The findings, published today in Clinical Infectious Diseases, show that many patients at high risk of developing complications from the flu missed out on antiviral medications’ potential benefits. At the same time, others were exposed to adverse effects from antibiotics that offered them little or no benefit and contribute to antibiotic resistance.

The investigators analyzed data from 6766 patients treated for acute respiratory illness at 5 ambulatory care centers in the US Influenza Vaccine Effectiveness Network. Participants in the study were at least 6 months old, had a cough for not more than 7 days, and were tested for influenza with polymerase chain reaction (PCR).

Among all participants, 7.5% received a prescription for an antiviral medication—oseltamivir or zanamivir, which are neuraminidase inhibitors that specifically target the influenza virus. Of the entire group, 35% had PCR-confirmed influenza.

However, the investigators noted that few clinicians adhered to published guidelines. Antiviral medication is recommended for patients whose flu symptoms began within the previous 2 days and have risk factors for developing complications: being aged 2 years or younger or 65 years or older, pregnant, morbidly obese, or having 1 or more chronic illnesses, including compromised immunity.

But only 19% of the 1021 high-risk patients in the study who presented within 2 days of symptom onset were prescribed antiviral medications. Among the 2366 participants with PCR-confirmed influenza, 15% received an antiviral prescription. Of the 1825 patients with PCR-confirmed influenza for whom antiviral and antibiotic data were available, 30% were prescribed an antibiotic and 16% received an antiviral prescription. Antibiotic prescribing data covered amoxicillin-clavulanate, amoxicillin, and azithromycin.

The investigators noted that antiviral prescribing patterns varied widely among the 5 study sites, from 9% to 19% of patients with PCR-confirmed influenza. Antiviral prescriptions also were less frequent among children than adults, including high-risk children younger than 2 years.

In an accompanying editorial, Michael G. Ison, MD, MS, of the Northwestern University Feinberg School of Medicine in Chicago, wrote that the study “clearly demonstrates that antiviral treatment was underutilized and antibacterial therapy was likely overutilized by clinicians caring for outpatients with influenza.”

Ison added that a particularly troubling aspect of the findings “is that these [participants] were seen at centers with expertise in influenza research that should, theoretically, be more attuned to the importance of antiviral therapy, particularly in the high-risk [patients].”

He also noted that the study may underestimate antibiotic prescriptions for influenza because, in addition to the 3 for which data were available, other antibiotics such as cephalosporins and fluoroquinolones may be prescribed for acute respiratory infections. The drugs not only contribute to major public health risks from antibiotic resistance, they also expose patients to the risk of adverse effects including diarrhea and severe inflammation of the colon caused by Clostridium difficile infection.

The study’s authors wrote that their findings “reinforce the need for continuing education on the appropriate use of antibiotic and antiviral agents for patients presenting with acute respiratory illness.”

 

Author Insights: Time to Take Sex Ed Online

A pair of JAMA authors argue that online sex education will help kids get good information when and where they need it. Image: © iStock.com/gloch

A pair of JAMA authors argue that online sex education will help teens get good information when and where they need it. Image: © iStock.com/gloch

It’s time for evidence-based sexual education to meet teens where they are—online, argue a pair of authors in a JAMA Viewpoint today.

Providing adolescents with factual information about sexual health in public schools, particularly information about contraception, remains controversial in the United States—a situation reflected in the larger ongoing debate in US society about public policy and contraception.

This debate is a long-standing one. A 1966 JAMA editorial (reprinted in JAMA Revisited), noted that the American Medical Association took a stand to support the provision of contraception as an essential part of comprehensive health care, noting that some legal barriers to contraceptive access had been removed and that certain religious groups had softened their position on contraception. Last week, nearly a half century later, the US Supreme Court’s rule to affirm the right of certain employers to forgo providing health coverage for contraception based on religious grounds set off renewed debate about the intersection of public policy, sexual health, and religious convictions.

One way that educators and public health organizations can sidestep the controversy and educate teens about sexual health is to leverage digital tools to make comprehensive sex education (including information about contraception) available online, argue Victor C. Strasburger, MD, of the department of pediatrics at the University of New Mexico School of Medicine and Sarah S. Brown, MSPH, of the National Campaign to Prevent Teen and Unplanned Pregnancy.

 Victor C. Strasburger, MD, of the University of New Mexico School of Medicine and Sarah S. Brown, MSPH, of the National Campaign to Prevent Teen and Unplanned Pregnancy, make a case for online sex education in JAMA. Image: University of New Mexico.


Victor C. Strasburger, MD, of the University of New Mexico School of Medicine and Sarah S. Brown, MSPH, of the National Campaign to Prevent Teen and Unplanned Pregnancy, make a case for online sex education in JAMA. Image: University of New Mexico.

Strasburger discussed the issue with news@JAMA.

news@JAMA: What is the current state of sex education in the United States?

Dr Strasburger: Sex education has been controversial since I was a teen, and it really shouldn’t be. We really do a terrible job of educating kids about sex. Every other western country knows that teaching kids about sex makes them more knowledgeable. Some people think teaching them comprehensively will make them more sexually active, which isn’t true.

Teens get a lot of sex “education” from the media, which doesn’t provide good information about preventing pregnancy and the spread of sexually transmitted disease. It’s foolish to think 1 semester in middle school or high school can counteract the 15 000 sexual references they will see in the media each year.

We’ve come a long way with drug abuse prevention and bullying. But we haven’t made a lot of progress with sex education since I was growing up in the ’60s and ’70s.

news@JAMA: What are the advantages of online sex ed?

Dr Strasburger: The primary advantage is you don’t have to go through a conservative school board to get it implemented. The Internet offers free access to all. It’s also there 24/7. Teens need constant access to information about sexual health. They have questions that develop as situations arise. The Internet is always there. It’s a major resource that we have yet to use appropriately.

news@JAMA: What are the downsides?

Dr Strasburger: There’s a lot of bad information and pornography online. It’s unregulated. We worry that if health professionals create websites, they might be seen [by teens] as too totalitarian. You need teens involved in creating websites that are appealing. You can’t put a textbook online and expect it to be effective.

news@JAMA: How might local programs leverage online materials?

Dr Strasburger: We both feel the good will outweigh the bad if more people join in. It will give local communities more control. Communities vary in how conservative they are in their thinking. Communities can set up their own websites or text answer services.

The Internet can be a useful adjunct to traditional sex education. MTV has an app to identify the nearest place to find condoms. There is a website called bedsider.org that has good information and very funny videos. It takes the stigma out of teaching kids about sex.

news@JAMA: What’s your take-home message?

Dr Strasburger: Kids are getting a lot of sex education now, but it’s the wrong kind. We can use new technology wisely and in ways they will enjoy.

The controversy that exists around sex education is unnecessary and unscientific. There is no evidence that making kids smarter about sex makes them sexually active at a younger age. It’s time for the controversy to end.

Only 10% With Chronic Hepatitis C Complete Successful Treatment

Only 10% of the estimated 3.5 million US residents with chronic hepatitis C are successfully treated to achieve undetectable viral load. (Image:©/IvelinRadkov)

Only 9% of the estimated 3.5 million US residents with chronic hepatitis C are successfully treated to achieve undetectable viral load. (Image:©/IvelinRadkov)

Fewer than 10% of US residents with chronic hepatitis C virus (HCV) infection know of their illness, have access to health care, and have been treated successfully with antiviral therapy, according to a new study.

The finding comes 2 years after the Centers for Disease Control and Prevention recommended 1-time testing for the baby boom generation born between 1945 and 1965, which accounts for about 75% of all HCV infections in the United States. The study’s lead author, Baligh Yehia, MD, MPP, MSHP, of the University of Pennsylvania Perelman School of Medicine in Philadelphia, said the new data provide a baseline of hepatitis C care that health experts can use to monitor the effect and success of screening such a large population.

Reporting today in the journal PLOS ONE, Yehia and his colleagues conducted a meta-analysis to accurately estimate how many US residents with chronic HCV infection have completed the continuum of care from initial infection and diagnosis to treatment that achieves undetectable viral load. The researchers focused on 10 studies published from 2003 to 2013 from among the 10 000 they screened.

Their analysis showed that in the general US population, an estimated 3.5 million people have chronic HCV infection. About half have been diagnosed and are aware of their illness. Of the entire 3.5 million with chronic infection, some 43% had access to outpatient health care, 27% had their diagnosis confirmed with a hepatitis C virus RNA test, 17% had a liver biopsy to stage their disease, 16% had antiviral treatment prescribed, and about 9% achieved an undetectable viral load.

Last month, the Centers for Medicare & Medicaid Services began reimbursing for hepatitis C virus screening for baby boomers and those in high-risk groups. Six months earlier, the US Food and Drug Administration approved sofosbuvir, an oral medication that in clinical trials produced high rates of sustained viral suppression with fewer adverse effects than current treatments.

“The advent of new antiviral agents for hepatitis C will shorten treatment duration, likely increasing the number of people offered treatment, and improving cure rates,” Yehia said in a statement. “However, educating [health professionals] and the general public about prevention, care, and treatment; ensuring access to skilled treatment of hepatitis C; and addressing the high cost of these agents will be critical to maximizing the benefits of these new therapies.”