Current recs for JE-VC extended

Japanese encephalitis virus is a leading cause of encephalitis in Asia. The disease is mosquito borne where humans are incidental hosts who do not develop high-enough bloodstream concentrations to infect feeding mosquitoes. Culex tritaeniorhynchus mosquitos, an evening- and nighttime-biting mosquito, is the most important vector for transmission to humans.

Japanese encephalitis (JE) occurs primarily in rural agricultural areas, specifically in areas of rice production using flood irrigation. Although primarily rural, these ecologic conditions can be found near urban areas. Virus transmission is seasonal, with peak incidence in summer and fall. JE occurs throughout most of Asia and parts of the Western Pacific. The largest numbers of cases have been among people traveling to Thailand, followed by China, Indonesia, and the Philippines.

JE is primarily a disease of children in endemic countries, with annual incidences of 5-50 cases per 100,000 children. However, as adult travelers are both greater in number and lack protective antibody, they represent the majority of travel-acquired cases. Between 1973 and 2012, 65 cases of travel-associated JE among persons from nonendemic areas were reported in the literature. There was a median of 1 case per year, with 6 (9%) in children under 17 years of age. Among the six pediatric cases, the median age was 9 years, with a range of 1-11 years. Cases occurred most commonly between June and August, although they were reported year-round.

Symptomatic disease is often severe; however, the majority of cases are asymptomatic. Current estimates are 68,000 cases annually, with case fatality rates of 20%-30%. Thirty percent to 50% of survivors have significant neurologic, cognitive, or behavioral sequelae.

JE-VC, a formalin-inactivated vaccine derived from an attenuated virus strain and propagated in Vero cells, was licensed for use in children beginning at 2 months of age in May 2013. This is the only JE vaccine currently licensed and available in the United States. The JE-VC vaccine, manufactured as IXIARO, was licensed for use in adults in the United States, Europe, and Australia in 2009. The primary immunization series is two doses administered intramuscularly at 0 and 28 days.

The Centers for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP) reviewed the relevant data for a June 2013 meeting. The working group concluded that the overall risk of JE for most travelers to Asia is very low, but that the risk varies based on destination, duration, season, and activities. Prolonged travel in rural areas with active JE virus transmission may confer risks to travelers that are similar to risks in susceptible resident populations. Shorter-term travelers may still be at risk if their itinerary includes outdoor or nighttime exposure in rural areas during periods of active transmission. Short-term travel restricted to major urban areas confers minimal risk of JE.

ACIP recommendations for adults 17 years of age and older were approved in June 2009, and a booster dose recommendation was approved in February 2011. Recommendations state that health providers who are considering the use of JE vaccines for travelers must weigh the risk of travel-associated JE with the benefits and potential risks of the JE vaccine.

JE is a severe disease with substantial morbidity and mortality, and there is no specific treatment. A safe and effective vaccine is available; however, the vaccine is relatively expensive and the possibility of rare, serious adverse events cannot be excluded. The 2009 and 2011 recommendations for adults included the following:

• Travelers to JE-endemic countries should be advised of the risks of JE disease and the importance of measures to reduce mosquito bites.

• JE vaccine is recommended for travelers who plan to spend a month or longer in endemic areas during the JE virus transmission season.

• JE vaccine should be considered for short-term travelers to endemic areas if they will travel outside of an urban area, and if their activities will increase the risk of JE virus exposure.

• JE vaccine is not recommended for short-term travelers whose visit will be restricted to urban areas or times outside of a well-defined JE virus transmission season.

• If it has been 1 year since the primary series, a booster dose may be given prior to potential JE virus exposure.

• Data on the need for and timing of additional booster doses are not available.

A recommendation to expand the recommended use of JE-VC to children aged 2 months was approved by ACIP in June 2013. Their recommendation was based on the data demonstrating a high rate of seroconversion in children following the two-dose primary series, low rates of serious or systemic adverse events, and the lack of therapy for a serious disease.

In summary, JE-VC is recommended for travelers who plan to spend a month or longer in endemic areas during the JE virus transmission season. This includes long-term travelers, recurrent travelers, or expatriates who will be based in urban areas but are likely to visit endemic rural or agricultural areas during a high-risk season; the vaccine also should be considered for short-term travelers to rural endemic areas during virus transmission season, as well when there are outbreaks.

Dr. Pelton is chief of pediatric infectious disease and also is the coordinator of the maternal-child HIV program at Boston Medical Center. Dr. Pelton said he has attended and received honoraria for Novartis advisory board meetings on vaccines, although JE-VC has not been discussed. E-mail him at [email protected].

Japanese encephalitis virus is a leading cause of encephalitis in Asia. The disease is mosquito borne where humans are incidental hosts who do not develop high-enough bloodstream concentrations to infect feeding mosquitoes. Culex tritaeniorhynchus mosquitos, an evening- and nighttime-biting mosquito, is the most important vector for transmission to humans.

Japanese encephalitis (JE) occurs primarily in rural agricultural areas, specifically in areas of rice production using flood irrigation. Although primarily rural, these ecologic conditions can be found near urban areas. Virus transmission is seasonal, with peak incidence in summer and fall. JE occurs throughout most of Asia and parts of the Western Pacific. The largest numbers of cases have been among people traveling to Thailand, followed by China, Indonesia, and the Philippines.

JE is primarily a disease of children in endemic countries, with annual incidences of 5-50 cases per 100,000 children. However, as adult travelers are both greater in number and lack protective antibody, they represent the majority of travel-acquired cases. Between 1973 and 2012, 65 cases of travel-associated JE among persons from nonendemic areas were reported in the literature. There was a median of 1 case per year, with 6 (9%) in children under 17 years of age. Among the six pediatric cases, the median age was 9 years, with a range of 1-11 years. Cases occurred most commonly between June and August, although they were reported year-round.

Symptomatic disease is often severe; however, the majority of cases are asymptomatic. Current estimates are 68,000 cases annually, with case fatality rates of 20%-30%. Thirty percent to 50% of survivors have significant neurologic, cognitive, or behavioral sequelae.

JE-VC, a formalin-inactivated vaccine derived from an attenuated virus strain and propagated in Vero cells, was licensed for use in children beginning at 2 months of age in May 2013. This is the only JE vaccine currently licensed and available in the United States. The JE-VC vaccine, manufactured as IXIARO, was licensed for use in adults in the United States, Europe, and Australia in 2009. The primary immunization series is two doses administered intramuscularly at 0 and 28 days.

The Centers for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP) reviewed the relevant data for a June 2013 meeting. The working group concluded that the overall risk of JE for most travelers to Asia is very low, but that the risk varies based on destination, duration, season, and activities. Prolonged travel in rural areas with active JE virus transmission may confer risks to travelers that are similar to risks in susceptible resident populations. Shorter-term travelers may still be at risk if their itinerary includes outdoor or nighttime exposure in rural areas during periods of active transmission. Short-term travel restricted to major urban areas confers minimal risk of JE.

ACIP recommendations for adults 17 years of age and older were approved in June 2009, and a booster dose recommendation was approved in February 2011. Recommendations state that health providers who are considering the use of JE vaccines for travelers must weigh the risk of travel-associated JE with the benefits and potential risks of the JE vaccine.

JE is a severe disease with substantial morbidity and mortality, and there is no specific treatment. A safe and effective vaccine is available; however, the vaccine is relatively expensive and the possibility of rare, serious adverse events cannot be excluded. The 2009 and 2011 recommendations for adults included the following:

• Travelers to JE-endemic countries should be advised of the risks of JE disease and the importance of measures to reduce mosquito bites.

• JE vaccine is recommended for travelers who plan to spend a month or longer in endemic areas during the JE virus transmission season.

• JE vaccine should be considered for short-term travelers to endemic areas if they will travel outside of an urban area, and if their activities will increase the risk of JE virus exposure.

• JE vaccine is not recommended for short-term travelers whose visit will be restricted to urban areas or times outside of a well-defined JE virus transmission season.

• If it has been 1 year since the primary series, a booster dose may be given prior to potential JE virus exposure.

• Data on the need for and timing of additional booster doses are not available.

A recommendation to expand the recommended use of JE-VC to children aged 2 months was approved by ACIP in June 2013. Their recommendation was based on the data demonstrating a high rate of seroconversion in children following the two-dose primary series, low rates of serious or systemic adverse events, and the lack of therapy for a serious disease.

In summary, JE-VC is recommended for travelers who plan to spend a month or longer in endemic areas during the JE virus transmission season. This includes long-term travelers, recurrent travelers, or expatriates who will be based in urban areas but are likely to visit endemic rural or agricultural areas during a high-risk season; the vaccine also should be considered for short-term travelers to rural endemic areas during virus transmission season, as well when there are outbreaks.

Dr. Pelton is chief of pediatric infectious disease and also is the coordinator of the maternal-child HIV program at Boston Medical Center. Dr. Pelton said he has attended and received honoraria for Novartis advisory board meetings on vaccines, although JE-VC has not been discussed. E-mail him at [email protected].

Japanese encephalitis virus is a leading cause of encephalitis in Asia. The disease is mosquito borne where humans are incidental hosts who do not develop high-enough bloodstream concentrations to infect feeding mosquitoes. Culex tritaeniorhynchus mosquitos, an evening- and nighttime-biting mosquito, is the most important vector for transmission to humans.

Japanese encephalitis (JE) occurs primarily in rural agricultural areas, specifically in areas of rice production using flood irrigation. Although primarily rural, these ecologic conditions can be found near urban areas. Virus transmission is seasonal, with peak incidence in summer and fall. JE occurs throughout most of Asia and parts of the Western Pacific. The largest numbers of cases have been among people traveling to Thailand, followed by China, Indonesia, and the Philippines.

JE is primarily a disease of children in endemic countries, with annual incidences of 5-50 cases per 100,000 children. However, as adult travelers are both greater in number and lack protective antibody, they represent the majority of travel-acquired cases. Between 1973 and 2012, 65 cases of travel-associated JE among persons from nonendemic areas were reported in the literature. There was a median of 1 case per year, with 6 (9%) in children under 17 years of age. Among the six pediatric cases, the median age was 9 years, with a range of 1-11 years. Cases occurred most commonly between June and August, although they were reported year-round.

Symptomatic disease is often severe; however, the majority of cases are asymptomatic. Current estimates are 68,000 cases annually, with case fatality rates of 20%-30%. Thirty percent to 50% of survivors have significant neurologic, cognitive, or behavioral sequelae.

JE-VC, a formalin-inactivated vaccine derived from an attenuated virus strain and propagated in Vero cells, was licensed for use in children beginning at 2 months of age in May 2013. This is the only JE vaccine currently licensed and available in the United States. The JE-VC vaccine, manufactured as IXIARO, was licensed for use in adults in the United States, Europe, and Australia in 2009. The primary immunization series is two doses administered intramuscularly at 0 and 28 days.

The Centers for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP) reviewed the relevant data for a June 2013 meeting. The working group concluded that the overall risk of JE for most travelers to Asia is very low, but that the risk varies based on destination, duration, season, and activities. Prolonged travel in rural areas with active JE virus transmission may confer risks to travelers that are similar to risks in susceptible resident populations. Shorter-term travelers may still be at risk if their itinerary includes outdoor or nighttime exposure in rural areas during periods of active transmission. Short-term travel restricted to major urban areas confers minimal risk of JE.

ACIP recommendations for adults 17 years of age and older were approved in June 2009, and a booster dose recommendation was approved in February 2011. Recommendations state that health providers who are considering the use of JE vaccines for travelers must weigh the risk of travel-associated JE with the benefits and potential risks of the JE vaccine.

JE is a severe disease with substantial morbidity and mortality, and there is no specific treatment. A safe and effective vaccine is available; however, the vaccine is relatively expensive and the possibility of rare, serious adverse events cannot be excluded. The 2009 and 2011 recommendations for adults included the following:

• Travelers to JE-endemic countries should be advised of the risks of JE disease and the importance of measures to reduce mosquito bites.

• JE vaccine is recommended for travelers who plan to spend a month or longer in endemic areas during the JE virus transmission season.

• JE vaccine should be considered for short-term travelers to endemic areas if they will travel outside of an urban area, and if their activities will increase the risk of JE virus exposure.

• JE vaccine is not recommended for short-term travelers whose visit will be restricted to urban areas or times outside of a well-defined JE virus transmission season.

• If it has been 1 year since the primary series, a booster dose may be given prior to potential JE virus exposure.

• Data on the need for and timing of additional booster doses are not available.

A recommendation to expand the recommended use of JE-VC to children aged 2 months was approved by ACIP in June 2013. Their recommendation was based on the data demonstrating a high rate of seroconversion in children following the two-dose primary series, low rates of serious or systemic adverse events, and the lack of therapy for a serious disease.

In summary, JE-VC is recommended for travelers who plan to spend a month or longer in endemic areas during the JE virus transmission season. This includes long-term travelers, recurrent travelers, or expatriates who will be based in urban areas but are likely to visit endemic rural or agricultural areas during a high-risk season; the vaccine also should be considered for short-term travelers to rural endemic areas during virus transmission season, as well when there are outbreaks.

Dr. Pelton is chief of pediatric infectious disease and also is the coordinator of the maternal-child HIV program at Boston Medical Center. Dr. Pelton said he has attended and received honoraria for Novartis advisory board meetings on vaccines, although JE-VC has not been discussed. E-mail him at [email protected].