Microneedle influenza vaccine shows 100 percent efficacy

Scientists recently developed an influenza vaccine that has shown 100 percent efficacy against infection in mice and has potential to be used in developing countries.

The findings of the study were reported in the September issue of the journal Clinical and Vaccine Immunology. The new vaccine uses a microneedle patch to protect the patient against infection for more than one year after vaccination.

The microneedle patch is seven tenths of a millimeter in length and delivers a fraction of the amount of vaccine a typical immunization would deliver, causing less pain than a traditional vaccine would. The minimized dosage also decreases the risk of side effects, such as inflamed lungs.

The new vaccine uses dry virus-like particles instead of liquid containing the whole or an attenuated virus, as a traditional virus would. The dry substance simply needs to be placed on the needle, which eliminates the needs for refrigeration, a key concern in the developing world.

"This method can induce higher levels of IgG2a antibodies as well as rapid recall immune responses following lethal challenge infection," Sang-Moo Kang, a researcher on the study of Georgia State University, said. "Our previous study showed that microneedle vaccination induced higher levels of antibody-secreting cells in spleen and bone marrow compared to intramuscular vaccination."

Previous studies for VLP-coated microneedles against influenza showed higher protection against infection than the traditional intramuscular immunization. The new vaccine also showed higher long-term efficacy, keeping mice protected 14 months after vaccination.

The new vaccine offers a pain-free and easy-to-administer method of vaccination, which may increase demand for the vaccine. Kang said it is likely patients can administer the vaccine themselves, ideal for developing countries where access to health care may be limited.