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Avian influenza, actually killed a dolphin, where is the vaccine?

author:Vaccines and Science

Earlier this year, a dead bottlenose dolphin was spotted on Horseshoe Beach in Dixie County, Florida. When a marine animal rescue team at the University of Florida conducted a routine autopsy, nothing was immediately suspected, and the common cause of death test resulted in negative.

Avian influenza, actually killed a dolphin, where is the vaccine?

News source: https://t.cn/A6SE4bMp

"However, the dolphin's brain and the tissues around it are inflamed," said Robert Ossiboff, associate professor of veterinary anatomy pathology at The University of Florida, "This finding is very unusual." ”

Dr Andrew Allison, Assistant Professor of Veterinary Virology at the University of Florida, added: "Although avian influenza infection has never been recorded in dolphins, the high incidence of the virus in wild birds in spring – particularly aquatic birds such as ducks, seagulls, terns and herons – is not inconceptible that dolphins come into contact with dying birds or dead birds near the coastline. ”

Wild birds that die from highly pathogenic avian influenza often find neurological symptoms of the virus in their brains, and inflammation of the dolphins' brains and meninges can also be caused by the virus.

Based on these initial suspicions, the University researchers sent dolphin brain and lung samples to the Bronson Animal Disease Diagnostic Laboratory in Florida.

There, suspicions were confirmed as samples tested positive for highly pathogenic avian influenza.

The case is the first time highly pathogenic avian influenza has been detected in cetaceans in North America.

The virus recovered from the dolphins belongs to the evolutionary branch 2.3.4.4b of the Eurasian H5 virus lineage.

In 2022, wild birds circulated H5 evolutionary branch 2.3.4.4b highly pathogenic avian influenza across the United States.

As of September 7, 2022, the U.S. Department of Agriculture reported that 39 states have confirmed the loss of more than 43 million poultry due to highly pathogenic avian influenza this year.

Avian influenza, actually killed a dolphin, where is the vaccine?

Highly pathogenic avian influenza is already endemic in birds. However, fatal infections were also reported in 2022 by red foxes, raccoons, striped skunks and harbor seals, and highly pathogenic avian influenza was also found to be the cause of black bear deaths.

The H5N1 avian influenza virus emerged in southern China in 1996 and later caused a large poultry outbreak in 1997, infecting 18 people. The H5N1 avian influenza virus re-emerged in 2003 and spread throughout Asia and later to Africa, Europe and the Middle East.

Since 2003, more than 860 human infections with the H5N1 avian influenza virus have been reported in 19 countries, with about 53% of these cases resulting in death.

Because seasonal flu vaccines don't protect people from avian flu infection, the U.S. FDA approved Seqirus' Audenz, a cell-based adjuvant influenza H5N1 vaccine, in 2020.

Dr. Tao commented

China is a high-risk area for highly pathogenic avian influenza.

In 2004, international and domestic experts believed that the highly pathogenic avian influenza (H5N1) virus could mutate further, resulting in a greater risk of human-to-human transmission of the epidemic, a high degree of harm, and extremely serious consequences if it occurs. The mainland immediately listed the virus as a Category B infectious disease and administered it in accordance with Category A infectious diseases. In 2013, the mainland also included highly pathogenic avian influenza (H7N9) in the management of Class B infectious diseases.

In October 2005, the siblings in Xiangtan County, Hunan Province, were identified as the first Chinese mainland people infected with highly pathogenic avian influenza (H5N1), and one of them died.

Avian influenza, actually killed a dolphin, where is the vaccine?

After 2005, human infections with highly pathogenic avian influenza rose and fell in Chinese mainland, but almost none reported more than 10 cases in 2014.

The number of cases suddenly soared to 325 in 2014, followed by 204, 216 and 646 in the next three years, before suddenly falling back to single digits in 2018.

Avian influenza, actually killed a dolphin, where is the vaccine?

Chinese cases of infection with highly pathogenic avian influenza are distributed annually

Based on the cumulative number of monthly reports of notifiable infectious diseases, the actual number of cases may be revised annually

The mainland has long been developing a vaccine for highly pathogenic avian influenza. In 2008, Kexing's pandemic influenza virus (H5N1) vaccine, Pan'er Laifu (Sinopharm S20080005), was approved for marketing, but it was only used for national reserves.

Avian influenza, actually killed a dolphin, where is the vaccine?

Highly pathogenic avian influenza vaccine – Pan Er LaiFu

There are many types of highly pathogenic avian influenza viruses that can infect humans, H5N1 in the early days and H7N9 in the later years. Last year, another case of H10N3 virus was reported in Zhenjiang, Jiangsu Province, and another H3N8 virus was reported in Zhumadian City, Henan Province this year. There are also H7N1, H7N2, H7N3, H7N7, H9N2 and other types can infect humans.

Avian influenza, actually killed a dolphin, where is the vaccine?
Avian influenza, actually killed a dolphin, where is the vaccine?

Highly pathogenic avian influenza is really too much to prevent, and the vaccine is too late to update.

Although there is already a human-used avian influenza vaccine for H5N1 (Panerlevo) on the mainland, there is no vaccine for other types of avian influenza, and in terms of technical reserves, there are two gaps with the Audenz approved by the United States mentioned above.

First of all, Paneraffol is cultured based on chicken embryos, and Audenz is cell cultured.

Cell culture techniques can free themselves from dependence on chicken embryos (which must be hatched from specifically required fertilized eggs) and be more secure in terms of production.

At the same time, after the influenza virus is cultured in chicken embryos, adaptive changes may occur, resulting in its incompatibility with the actual circulating virus, which will affect the protective effect of the vaccine. There is already evidence that cell-cultured influenza vaccines are superior to chicken embryo cultured vaccines.

Avian influenza, actually killed a dolphin, where is the vaccine?

The U.S. FDA explains the advantages of cell culture flu vaccines

https://t.cn/A6SEbnU8

Secondly, Paneraffle uses the traditional adjuvant aluminum hydroxide, and Audenz uses the innovative adjuvant MF59.

At present, most of the seasonal influenza vaccines given every year do not use adjuvants, and the effect is generally average. Scientists are also exploring how to enhance the effectiveness of influenza vaccines, one strategy is to make a high-dose vaccine, and the other is to add adjuvants.

Seqirus, which makes Audenz, has a patent for the MF59 adjuvant, which it uses in both the seasonal flu vaccine Flud and the avian influenza vaccine Audenz.

MF59 is a mature, safe and effective vaccine adjuvant that has been licensed in more than 30 countries since it was first approved in 1997. More than 200 million doses have been vaccinated using this adjuvant, accumulating a large amount of data on safety and efficacy.

The use of MF59 adjuvants means that audenz's immune effect is likely to be superior to that of Panlefour. In addition, this increased immune effect may also reduce the amount of vaccine used, which is very helpful for increasing the supply of vaccines during the avian influenza pandemic.

Although humanity is currently choked by COVID-19, the real threat is probably the influenza virus that has caused many pandemics in history.

100 years after the 1918 flu, scientists are widely concerned that the flu virus will once again undergo a major mutation, causing all humans to be susceptible to a pandemic. If this happens, it's likely to be 100 times more terrifying than COVID-19.

Humans call COVID-19 "big flu," and maybe the flu virus is upset with this discrimination and is gathering dark forces to strike a fatal blow against humanity?

The question is: Is humanity ready for bird flu vaccines? Does being ready really work?

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