Yellow fever is a vector-borne viral hemorrhagic fever, which is transmitted by mosquitoes. This fever is common in South America and in sub-Saharan Africa. People travelling to endemic areas need to get vaccinated about 10-14days before their travel by the use of a live attenuated vaccine (17D). But there is a slight risk of the vaccine virus replicating despite it being attenuated. If this happens then it poses certain risks of causing neurotropic adverse events and anaphylaxis that may sometimes result in death. A need for safer vaccine has been explored in the last few years.
The answer maybe by using a cell-culture vaccine that reduces the risk of allergic reactions replication. The vaccine can be administered to the elderly, immunosuppressed patients, infants below 9-months and even to pregnant and nursing women.A cell-culture vaccine XRX-001 for yellow fever was tested by scientists in 60 healthy individuals between 18-49 years of age. They studied the safety, adverse event profile and immunogenecity of the vaccine. The XRX-001 is a whole virus β-propiolactone-inactivated yellow fever vaccine produced in Vero cell culture and adsorbed to 0.2% alum (aluminum hydroxide) adjuvant. It is manufactured by Xcellerlex. Subjects who qualified for the study were previously not vaccinated against yellow fever, Japanese encephalitis or tick-borne encephalitis and nor did they have a history of overseas travel to the tropics. Two shots of this vaccine which contained 0.48µg or 4.8µg antigen were administered intramuscularly 21days apart. Scientists then measured levels of neutralizing antibodies at baseline on days 0, 21, 31 and 42.
It was found that individuals who received 4.8µg of this inactivated vaccine induced development of neutralizing antibodies in 100% subjects and in 88% subjects who were administered 0.48µg of antigen. Following the administration of the second dose the level of antibodies increased by day 10. This antibody level was significantly higher among individuals who received 4.8µg of the vaccine. No serious side-effects were reported except for pain, tenderness and itching at the injection site in some cases. Only 1 case of skin reaction (urticaria) was reported on day 3 after administration of 4.8µg of vaccine. The safety of the vaccine was assessed on the basis of local and systemic reactions.
Thus scientists concluded that this two-dose regime of the vaccine has the potential to be a safer alternative to the existing live attenuated vaccine (17D). This was the first clinical trial of the vaccine. A second clinical has to be initiated which would evaluate the durability of antibody response which has been reported in this trial.
Reference
Thomas P. Monath, M.D., Elizabeth Fowler, Ph.D., Casey T. Johnson, D.O., John Balser, Ph.D., Merribeth J. Morin, Ph.D., Maggie Sisti, B.S., and Dennis W. Trent, Ph.D.
New England Journal of Medicine 2011; 364:1326-1333April 7, 2011
Yellow Fever | Acute Viral Hemorrhagic Fever - Causes, Symptoms, Diagnosis & Treatment
Yellow fever is a hemorrhagic fever that is transmitted by infected mosquitoes and it can lead to liver failure and death.
Yellow fever is a hemorrhagic fever that is transmitted by infected mosquitoes and it can lead to liver failure and death.
About Mosquito Diseases
Mosquito-borne diseases, like malaria, filaria, dengue, etc are common in places conducive of mosquito breeding. Swamps, ponds and stagnated drainage provide optimal breeding ground for mosquitoes.
Mosquito-borne diseases, like malaria, filaria, dengue, etc are common in places conducive of mosquito breeding. Swamps, ponds and stagnated drainage provide optimal breeding ground for mosquitoes.
Dengue and Dengue Fever - Symptoms, Causes, Diagnosis, Treatment & Prevention
Dengue is a tropical disease caused by mosquitoes carrying the dengue virus. Symptoms include fever, joint & muscle ache, fatigue, nausea and skin rash.
Dengue is a tropical disease caused by mosquitoes carrying the dengue virus. Symptoms include fever, joint & muscle ache, fatigue, nausea and skin rash.
Drug Resistance – Antibiotic or Antimicrobial Resistance
Drug resistance is often a problem in malaria, tuberculosis, HIV, sexually transmitted diseases and hospital acquired diseases. Judicious use of antibiotics can control the problem.
Drug resistance is often a problem in malaria, tuberculosis, HIV, sexually transmitted diseases and hospital acquired diseases. Judicious use of antibiotics can control the problem.
