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  • Tuesday ,03 December 2019
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New discovery could spell end to seasonal flu

by DW

Technology

00:11

Thursday ,28 November 2019

New discovery could spell end to seasonal flu

 A potential breakthrough discovery of new antibodies could lead to a universal vaccine. If successful, it could protect against all types of deadly influenza viruses and even prevent pandemics, a study shows.

Immunologist Ali Ellebedy was working on a study analyzing the immune response to flu infection in humans. During his research, he spotted a new type of powerful antibody in a blood sample from a patient infected with human influenza virus. 
Ellebedy then sent samples of the antibody to Florian Krammer — a microbiologist who proved the effectiveness of the antibodies by testing them against extensive samples of virus proteins dating back to the 1970s. These proteins, called neuraminidase, enable the virus to spread through the human body.
The study, which was jointly conducted by Scripps Research, Washington University s School of Medicine in St. Louis and the Icahn School of Medicine in New York, was published in the October issue of Science.
Future vaccine could survive antiviral resistance
Krammer told DW that the beauty of this new antibody, called 10G1, is that it binds to the parts of the virus that never change. This means that even if new strains of influenza viruses are detected, a potential vaccine containing new antibodies would still be effective.
Moreover, the antibody has a powerful potential to attack both A and B subtypes of influenza viruses, making it an even better candidate for a universal vaccine that would combat human, swine, and bird strains, as well as other rarer strains of lethal flu viruses.
There are three types  of influenza viruses that affect humans. These are A, B, and C. Type A causes epidemics of seasonal flu. Among these are swine H1N1, bird H5N1, and human influenza flu H3N2. Type A viruses circulate between humans and other species, whereas type B and C are only known to exist in humans, causing mild infections and usually without symptoms.
DW analyzed data about virus activity throughout the US and Europe, sourced by the World Health Organisation s Global Surveillance and Response System (GISRS). The results, presented in the heatmap below, show that there has been a steady rise in influenza virus activity for both A and B virus subtypes, especially in the US, the UK, Portugal, Germany and Croatia.
Moreover, the results point to a high activity in the first and last weeks of the year.
Not only to prevent, but also to cure
Even though commonly mistaken for a cold due to similar symptoms— like coughing, a runny nose, sneezing, and experiencing a high fever — seasonal flu can be very dangerous. Untreated influenza can have fatal outcomes, as it can lead to severe respiratory infections. This is particularly the case for sensitive groups like infants, pregnant women, the elderly and people with chronic diseases.
 
One of the biggest problems with current vaccines is that they usually last one season before the virus mutates. However, researchers working on this study also tried to create resistant viruses in the lab to test whether the new antibody would still work. The results proved that the antibodies still bound to the virus and neutralized it.
 
The antibodies proved to be effective even against strains of the virus resistant to Tamiflu, a powerful cure used to treat severe cases of influenza viruses like swine and bird flu.
 
"Infected mice [in the study] reacted very well to these antibodies even three days after they were infected, and the window for Tamiflu was closed. This means that the discovered antibodies would have a potential for the development of both vaccine and a cure," Krammer told DW.
Rise in global deaths from flu
There is a steady rise in global annual deaths from influenza viruses. Now, there are an estimated 290,000 to 600,000 mortality cases per year, but it is still hard to determine real numbers.
"There is pretty good data for North America and Europe, so it really depends on how good the surveillance systems are. Unfortunately there are a lot of countries that don t have good surveillance systems for influenza."
 
Further data analysis by DW shows that the year 2018 saw particularly high influenza virus activity compared to the past several years.
 
The most common flu infections were caused by the virus A, which was not subtyped. Krammer told DW that unsubtyped A viruses mean that it is hard to identify if the virus belongs to the H1N1 swine flu, or H3N2, which is human influenza virus.
 
A new report from the American Center for Disease Control and Prevention also suggests that influenza season in the United States started earlier this year, and that widespread virus type A activity has been recorded in Puerto Rico, and seven other states including Texas, Alabama, and Nevada.
 
On the other hand, Krammer explained that flu seasons vary in the northern and southern hemispheres. In the north, flu seasons are common in winter, but in countries like China and Singapore, influenza is spread throughout the year because there is no real winter. That makes it even more difficult to determine the real burden of influenza.
"It s still not quite clear to what extent influenza seasons are influenced by the changing weather and to what extent they are influenced by the changing behavior of humans during these weather changes," said Krammer.
High risk of pandemic
Krammer pointed out that the chances for a global pandemic are increasing. It s hard to predict when the next big pandemic will happen, he said, but he is certain it will happen again.
He also explained that the most deadly influenza virus type, which dominated flu seasons over the past few years, is the human influenza virus H3N2. But it s impossible to say which virus will cause the next big outbreak and cause the most deaths.
"We have approximately three to four pandemics per century. We had the one in 1918, 1957, 1968 and one in 2009, so it s not very predictable," he said.
"The chances for a pandemic are, however, increasing because there is a lot more global interaction. Pandemic viruses come from avian species, like wild birds, chickens, ducks, where all these influenza viruses circulate. If we look at the number of chickens we raise for food, they are increasing, because the global population is increasing and we need to feed people."
Prevention best way to avoid lethal flu infections
Even though newly discovered antibodies have enormous potential for the development of a truly universal vaccine and cure for influenza, it will take years of costly clinical trials before it hits the market, Krammer said.
The first step is to examine if it s possible for all humans to develop the 10G1 antibodies.
Until a universal vaccine is developed, one of the best ways to stay safe is to take precautionary measures, Krammer suggested.
"First, get vaccinated. The vaccines we have now are not perfect, but they really work. The second step is to keep ourselves healthy. If we are healthy, infections have less impact. The new generation of a vaccine we have now is against four viruses which circulate in humans which are H1N1, H3N2 and two types of influenza B viruses."