attenuated vaccine :: Article CreatorMSU-developed Vaccine, Delivery System Ease Antibiotic Resistance In Catfish
Contact: Meg Henderson
STARKVILLE, Miss.—Mississippi State scientists have developed a live-attenuated oral vaccine and delivery platform that have put the brakes on the spread of antimicrobial resistance in catfish, resulting in significant cost benefits for Mississippi producers.
A team of scientists at Mississippi State's Thad Cochran National Warmwater Aquaculture Center have developed a groundbreaking vaccine, preventing a deadly catfish disease while controlling antimicrobial resistance. (Photo submitted)
The success of the MSU team represents a breakthrough in catfish health, food safety and industry sustainability, and demonstrates the significant impact MSU and its Thad Cochran National Warmwater Aquaculture Center in Stoneville have on an important Southern U.S. Commodity.
Since the 1980s, producers have been swimming upstream against the pervasive bacterium E. Ictaluri, which causes enteric septicemia of catfish, or ESC. This disease targets the fish's brain, resulting in abnormal behavior and swimming patterns, swelling, ulcers and, eventually, death. The economic impact of ESC in the catfish fingerling industry ranges between $10 million and $17 million annually.
Since 2019, an experimental vaccine developed by scientists in the university's Mississippi Agricultural and Forestry Experiment Station has been administered under veterinary prescription on participating catfish farms, with oversight from the state veterinarian of Mississippi. These farms, which also receive diagnostic services from the MSU College of Veterinary Medicine Aquatic Research and Diagnostic Laboratory, provide researchers at NWAC with a distinct opportunity to assess the vaccine's impact beyond production records. By integrating diagnostic data with field observations, NWAC researchers are evaluating the vaccine's effectiveness, its influence on fish health and production, and its potential impact on antibiotic use and antimicrobial resistance, or AMR.
Historically, the incidence of AMR among E. Ictaluri isolates from disease case submissions was low in both channel and hybrid catfish fingerlings. This means that, overall, antibiotic-treated feed had been a reliable ESC treatment for many years. Beginning in 2014, the percentage of isolates with reduced sensitivity to antibiotics increased substantially, peaking in 2018, when nearly half of E. Ictaluri isolates demonstrated reduced susceptibility to approved treatments. At the same time, orders for medicated feed began increasing in 2013, peaking in 2017.
The team's development of a new vaccine and delivery system appears to have yielded tremendous results. To date, about 300 million fingerlings across 2,500-3,000 acres at participating farms have received the vaccine each year, with more than 16,000 total acres vaccinated since 2018. From 2018-2024, as participating farms were administering the ESC vaccine, orders for various medicated feeds dropped 69-78%. And as antibiotic use plummeted, so did reported instances of resistant isolates—by over 98%.
"The correlation between our vaccine and decreased AMR may be circumstantial, but these data suggest our approach can reduce reliance on antibiotics, and they underscore the benefits of preventative approaches to managing bacterial diseases in aquaculture," said Matt Griffin, a research professor at MSU's College of Veterinary Medicine.
Equally important is the team's mechanized delivery system developed by Mississippi Agricultural and Forestry Experiment Station scientists at NWAC and in MSU's Department of Agricultural and Biological Engineering. The delivery system allows for in-pond vaccination of older, immunocompetent fish—increasing the vaccine's efficacy. This innovative platform has reduced disease-related losses, improved survival rates and contributed to overall economic sustainability in catfish farming.
"Our delivery system is key to the vaccine's success," said David Wise, MAFES research professor and NWAC coordinator. "It could also be used for other vaccines currently in development for fingerlings or food fish."
As a result of more fingerlings surviving and growing to their full potential, producers are reaping the economic benefits from a healthier harvest. ESC cases fluctuate from year to year and among both species of catfish, but the economic gains from the vaccination treatments are considerable, nonetheless, even when factoring in the cost.
"On-farm research shows that the net economic benefits to channel and hybrid catfish producers range from $1,800 to $2,300 per acre, depending on the fish type and production strategies," said Ganesh Kumar, MAFES associate research professor in MSU's Department of Wildlife, Fisheries and Aquaculture.
Moreover, by reducing their reliance on antibiotics, farmers can control bacterial infections more effectively over the long term.
"Judicious use of the available antibiotics remains crucial for maintaining their effectiveness. Although orally delivered vaccines are effective, not all fish eat every day, leaving a portion of the population vulnerable," Griffin said. "Responsible antibiotic use is vital to preserving the efficacy of the few approved antibiotics, especially in cases of incomplete vaccine coverage or outbreaks of other bacterial diseases."
Research for the development and administration of the vaccine has been supported by several entities, including catfish producers, the USDA's Agricultural Research Service and its National Institute of Food and Agriculture, MSU's MAFES and College of Veterinary Medicine.
"The vaccine's success shows that recovery is possible," said Maural Sowlat, an assistant clinical professor in the College of Veterinary Medicine. "Even though we still see occasional isolates with reduced susceptibility, vaccines can reduce the need for antibiotics."
For more information about the Mississippi Agricultural and Forestry Experiment Station, visit www.Mafes.Edu. To learn more about the Thad Cochran National Warmwater Aquaculture Center, visit www.Tcnwac.Msstate.Edu. For more on the College of Veterinary Medicine, visit www.Vetmed.Msstate.Edu.
Mississippi State University is taking care of what matters. Learn more at www.Msstate.Edu.
'Made In India' Dengue Vaccine Likely To Be Launched Next Year. Here's What We Know
India may soon see a major leap forward in its battle against dengue, as a 'Made in India' version of the vaccine 'Qdenga' could be launched as early as next year.
The vaccine, originally developed by Japanese pharmaceutical company Takeda, is being manufactured in India through a collaboration with Hyderabad-based firm Biological E. As per a report by The Times of India, it is likely to be available by 2026 under the government's 'Make in India' initiative.
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Over the past few years, India has witnessed a troubling surge in dengue cases, leading to increased hospitalisations and fatalities. In 2023 alone, nearly 3 lakh cases were reported across the country, highest in the last 5 years, as per the information provided by the National Centre for Vector Borne Diseases Control.
Also read: Over 12 million cases, 8,000 deaths in 2024: Is dengue the new global pandemic?
Given the scale of the disease and its impact across India, the arrival of this dengue vaccine could prove to be a game-changer.
Here's what we know so far about Qdenga.
What is Qdenga, and how does it work?
Dengue fever is a viral infection spread by the Aedes Aegypti mosquito. The virus has four distinct strains — DENV-1 to DENV-4 — which has long made developing an effective vaccine particularly challenging.
That's where Qdenga, also known as TAK-003, comes in. This live-attenuated vaccine contains weakened forms of all four dengue virus serotypes and is designed to offer broad protection. It's administered in two doses, given three months apart.
Also read: In GraphicsHow do mosquitoes detect people, spread diseases?
"TAK-003 showed an excellent safety profile, and the immunogenicity after two doses against the four DENV serotypes was higher than 90 per cent among both adults and children/adolescents who were either seronegative or seropositive at baseline," researchers noted in a review published in the journal Vaccines, based on clinical trial data from multiple countries.
For context, "seropositive" individuals have previously been exposed to dengue, while "seronegative" individuals haven't, making the vaccine's performance across both groups especially effective.
Qdenga is a live-attenuated vaccine that contains weakened forms of all four dengue virus serotypes. It's administered in two doses, given three months apart. AI-generated representative image
As per Economic Times, Takeda's work on a dengue vaccine dates back to the 1980s, beginning with studies in Thailand. The company later joined hands with the US Centers for Disease Control and Prevention (CDC). In 2012, it launched one of its largest clinical trials — the TIDES study — which included 20,000 children across eight dengue-endemic nations. This was published alongside four-and-a-half years of follow-up data in The Lancet in 2023.
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In May 2024, the World Health Organization (WHO) granted prequalification status to Qdenga, after reviewing 19 studies that showed the vaccine reduced dengue cases by over 50 per cent.
With the WHO's green light, global agencies like UNICEF and the Pan American Health Organization could procure the vaccine. Qdenga has already been approved in several countries, including Brazil, Indonesia, Thailand, Argentina, and across the European Union.
Since its launch in 2023, more than 10 million doses of the vaccine have been administered.
All about its launch in India
Qdenga is currently undergoing clinical trials in India to gather local safety data, Derek Wallace, president of Takeda's global vaccine business unit, told The Times of India.
"We've already submitted a comprehensive data package that supported registration in 40 countries, and we anticipate the vaccine will be licensed in India in 2026," he said.
Wallace also confirmed that the vaccine will be launched simultaneously in both the private and public sectors.
Qdenga is currently undergoing clinical trials in India to gather local safety data. It will be licensed in India in 2026. Image for Representation. Reuters
"Like in many other countries, India's National Immunisation Program is very paediatric-focused. The initial conversation aligns with WHO guidelines for implementing public programs for the paediatric population. However, we are introducing the vaccine in the private sector for both paediatric and adult populations," he added.
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Also read: Russia's cancer vaccine is ready. Here's why it matters
The Indian rollout will be supported by Hyderabad-based Biological E, which will locally manufacture the vaccine. While Takeda's German facility currently produces single-dose vials, Bio E will handle the production of both single- and multi-dose formats for the Indian market.
"Our goal is to produce 100 million doses annually by the end of the decade, with Bio E contributing half of that," Wallace said. Bio E will also become Takeda's exclusive manufacturer for multi-dose vials, formats that are preferred in government health programmes due to their affordability, easier storage, and simpler logistics.
With input from agencies
End of Article
Kennedy Revives False Claim Of 'fetal Debris' In MMR Vaccine
WASHINGTON >> U.S. Health secretary Robert F. Kennedy Jr. Reprised various misleading claims about vaccines this week, including that the measles vaccine contains cells from aborted fetuses and the mumps vaccination does not work.
Kennedy's comments come as the U.S. Battles one of its worst outbreaks of measles in 25 years. Scientists have warned that the U.S. Is at a tipping point for the return of endemic measles, declared eradicated nationally in 2000, and say U.S. Public health officials like Kennedy should provide urgent endorsement for highly effective vaccines.
Two children have died and hundreds more have been infected in the outbreak in Texas, which is centered in a Mennonite community and has spread to neighboring states, including New Mexico, Oklahoma, and Kansas.
Kennedy, who became the nation's top health official in February, has for decades helped sow doubts regarding the safety and efficacy of vaccines, contributing to a decline in vaccination rates.
Kennedy says he is not opposed to vaccines, but has begun to revive some of the unproven or debunked theories he promoted as a lawyer and public figure, now from his perch at the U.S. Health and Human Services Department.
"There are populations in our country, like the Mennonites in Texas, (who) were most afflicted, and they have religious objections to the vaccination, because the MMR vaccine contains a lot of aborted fetus debris and DNA particles, so they don't want to take it," he said in a News Nation interview on Wednesday.
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Kennedy was referring to the combined Measles, Mumps and Rubella vaccine. The vaccines do not contain "fetal debris" from abortions or intact fetal cells, vaccine experts said.
The rubella portion of the vaccine is produced from a fetal cell line originating from an abortion that took place in the 1960s. The MMR vaccine does not contain the cells in its final form.
The cells are derived from fetal cells that have been replicated over decades in test tubes in laboratory settings, thousands of times removed from the original ones.
"The virus is grown in these cells, then this virus is purified, meaning everything other than the virus is filtered out, and all that's left is this attenuated virus that can't make you sick," said Dr. Miriam Laufer, Interim Director of the Center for Vaccine Development and Global Health at the University of Maryland.
According to a fact sheet on how vaccines are made from the Children's Hospital of Philadelphia at the University of Pennsylvania, the amount of DNA involved in final vaccine preparation is minimal; billionths or trillionths of a gram.
"While the final vaccines do not contain intact fetal cells, they may contain trace amounts of cell-derived materials, such as fragments of DNA," said Dr. Paulo Verardi, Professor of Virology and Vaccinology and the University of Connecticut.
The Department of Health and Human Services did not respond to a request for comment.
Kennedy also said this week that the mumps portion of the vaccine does not work and that there were safety concerns over it.
"The problem is really with the mumps portion of the vaccine and the combination. That combination was never safety tested," he said on Monday at a live televised town hall event hosted by TV host Dr. Phil.
Two doses of the MMR vaccine provide around 86% protection against mumps, according to the U.S. Centers for Disease Control and Prevention.
While it is true that vaccine protection can wane over time, the rate varies depending on the disease and vaccine, Verardi and other vaccine experts said.
"For mumps in particular, immunity can decline, so adults vaccinated in childhood may become susceptible again. Still, vaccinated individuals generally experience a milder illness if infected, which is still a key benefit of vaccination," he said.
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