A COVID-19 vaccine might come and not using a needle, the newest vaccine to guard with out jabbing
Oral vaccines have been around for many years. Image Credit: Shutterstock
Vaccines are traditionally given with a needle, but this is not the only way. For example, certain vaccines can be delivered orally, as drops on the tongue, or through a jet-like device.
Vaccines that seem particularly suitable for needle-free technology are DNA-based vaccines, including a COVID-19 vaccine developed in Australia.
Needle-free vaccines are attractive because they cause less pain and stress to people with needle phobias. But they have other advantages.
Jet injectors and beyond
The earliest needle-free injection systems date back to 1866 and used jet injectors. These handheld devices used pressure to penetrate the skin and deliver drugs.
They grew in popularity around the mid-20th century and were used to deliver vaccines against typhoid, polio, and smallpox.
A hepatitis B outbreak related to their use meant they were discontinued in the 1980s. However, research picked up again in the 1990s. The variations included a spring-loaded jet injector (a spring is released to deliver the drug), a battery-powered jet injector, and a gas-powered jet injector.
Jet injection has also been used in dental care to administer local anesthetics.
In addition to jet injection, oral vaccines such as rotavirus, cholera, polio and typhoid have been around for several decades and are still used in various parts of the world today. They can come as a liquid or a tablet.
More recently, researchers and biotechnology companies have developed vaccines that you breathe, such as: B. nasal sprays and skin patches. These are mostly still in clinical tests.
DNA-based vaccines and the gene gun
DNA vaccines were an accidental discovery as a result of early gene therapy experiments in the 1990s, in which injecting DNA into muscle unexpectedly triggered an immune response.
A DNA vaccine is used to deliver a small amount of the virus’ genetic material into cells under the skin. These cells then express the DNA as viral proteins. The body recognizes these as foreign and stimulates an immune response.
DNA vaccines are easy and cheap to make in large quantities and are relatively safe because they do not contain infectious agents such as live viruses.
Scientists have studied a number of ways to deliver DNA vaccines either with or without a needle. The needle-free methods include ultrasound (sound waves) and electroporation (electrical impulses), which destroy cell membranes and move DNA into cells.
The gene gun, or the “biojector 2000”, a form of jet injector, appears to be the most effective method. This uses pressure to inject DNA into deep layers of the skin. Because it improves the distribution of the vaccine deeper into the injection site, this method uses far less DNA than injecting it with a needle to create the same immune response.
However, no DNA vaccine has yet been approved for use in humans. Although needle-free DNA vaccines have been successful in preclinical and early clinical trials, DNA vaccines are generally not as effective in generating immune responses against diseases such as HIV and cancer.
Needle-free COVID-19 competitors
The University of Sydney recently received federal funding to begin human trials of a “liquid jet” injector to deliver its DNA vaccine.
Liquid jet injectors use small amounts of liquid that are forced through a tiny opening (smaller than a human hair). This ultra-fine, high pressure current penetrates the skin, where the cells take up the vaccine and stimulate the immune cells.
This method has been effective in several clinical trials against HIV and is currently used to deliver some influenza vaccines.
Other COVID-19 needle-free vaccines under development include a bandaid-like patch made of 400 tiny needles, a nasal vaccine, an oral vaccine in tablet form, and a needle-free device that delivers an mRNA vaccine.
Vaccines based on mRNA work similarly to DNA vaccines.
advantages and disadvantages
Advantages of needle-free vaccine technology, especially jet injectors, include:
- They can be much more acceptable to people who are afraid of needles, including children
- There is no risk of being accidentally injured with a needle
- They eliminate needle disposal (up to 500 million needles are thrown in the landfill every year after vaccinations, and 75 million of them could be infected with blood-borne diseases).
- They improve vaccine delivery into the skin and use a lower volume of vaccine.
- Start-up costs for users of the device, including the purchase of weapons devices and access to gas / air systems to power them
- Employees delivering the vaccine will need specialized training and may not feel safe with the technology
- The device needs regular maintenance.
New needle-free vaccines could mark the end of the flu shot provided by The Conversation
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