Flu viruses adapt and mutate, making influenza vaccines less effective. New research – published in the journal Science – has found a way to break down the virus’s defenses, giving future flu vaccines a boost.
Researchers from the University of California, Los Angeles – led by Ren Sun, a professor of molecular and medical pharmacology working in the university’s David Geffen School of Medicine – came up with a wholly new approach to developing flu vaccines.
Conventional vaccines reduce “immunogenicity” – that is, the ability of a substance to trigger the body’s immune response – by attenuating the virus. But the new approach preserves robust immune responses and works by identifying and eliminating the so-called immune evasion function of the viruses.
The body’s “first-line defense” function is for interferons to neutralize viruses as quickly as possible, while the “second line” of defense is to modulate our immune response, thereby offering us long-term protection against viruses. Interferons are signaling proteins that coordinate our immune response. As Sun explains, “If viruses do not induce interferons, they will not be killed in the first-line defense; and without interferons, the adaptive immune response is limited. “For these reasons, viruses have evolved strategies to evade detection and limit the production of the interferons by host organisms,” he added.
So, Sun and team found and disabled a genomic sequence of the influenza virus responsible for the interferon induction. “By disabling these interferon-evasion function,” explains first study author Yushen Du, “the engineered virus is weakened in typical hosts.” “At the same time,” she adds, “due to interferon stimulation, the engineered virus generates very strong immune responses.”
“With this approach, the safety and efficacy requirement of vaccines can potentially be achieved simultaneously. In traditional vaccine development, one is usually sacrificed for the other” said Sun.
The most encouraging aspect of this new research is that the vaccine would be nasal drops rather than a shot. Rarely do you contract an infection from injection. Virtually all viral and bacterial infections enter the body through the digestive or respiratory tracts. There, they detected by the GALT (gut associated lymphoid tissue). The GALT is truly the “first-line defense” of our immune system. It analyses the infection sending vital information to the thymus for the body to mount an immune response.
Injected vaccines bypass this line of defense presenting the “second-line defense” (cellular immunity) with a new enemy with no advance warning. This confuses the immune system and, in my opinion, is one of many factors that reduces the effectiveness and increases the side effects associated with vaccination.
However, I also have some reservations about this new approach. This year’s flu, H2N3 has been more lethal in young, healthy individuals because the body’s strong immune response is what kills them. This is what made the Spanish Flu of 1918, the mother of this strain, so virulent.
The flu epidemic of 1918-19 infected an estimated 500 million people world-wide, a third of the population. The death toll was 20-50 million over the course of two years.
The Bottom Line:
Our immunization program needs to be rethought and revamped. Although the science has advanced, the concepts are over 100 years old. Maybe the use of nasal drops targeting proteins in the virus is a step in the right direction.
Source: Medical News Today January 22, 2018
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