Saturday, September 23, 2023

Is There A Vaccine For Norovirus

What Does The Government Do To Protect Me

ASU develops norovirus vaccine from tobacco plant

In Canada, several government organizations work together every day to keep your food safe:

  • Health Canada makes food safety standards and policies to help minimize the risk of foodborne illnesses.
  • The Canadian Food Inspection Agency enforces these policies and standards and carries out inspections to make sure the food industry meets its food safety responsibilities. The CFIA works with Health Canada to make sure that foodborne illness is detected early and warnings go out to the public quickly.
  • The Public Health Agency of Canada studies the incidence and causes of diseases in Canada, conducts outbreak surveillance, and coordinates outbreak response.

The Government of Canada works very hard to protect your health and safety:

  • We are carrying out a five-year Food and Consumer Safety Action Plan, to strengthen and modernize Canada’s safety system and make sure you can have confidence in the quality and safety of the food, health and consumer products you buy.
  • We are investing $75 million more in Canada’s food safety system to hire more inspectors, update lab technology, and improve communication with Canadians.
  • We support and participate in public awareness campaigns about safe food practices, like the Canadian Partnership for Consumer Food Safety Education’s Be Food Safe program, which encourages Canadian consumers to think of food safety at every step of the food handling process, from shopping for groceries to re-heating leftovers.

Who Is At Risk Of Getting Severe Norovirus Illness

Most people will recover from a Norovirus infection with no complications. The symptoms of Norovirus infection may be more severe for infants, young children, the elderly and those with weak immune systems. Dehydration can be more serious for these individuals who should seek medical attention if this becomes severe.

Norovirus Oral Tablet Vaccine Enters Phase 1b Trials

Vaxart enrolled its first participants for its dose-ranging and boosting regimen studies.

South San Francisco-based biotechnology company, Vaxart, announced it has enrolled its first patients in 2 phase 1b trials evaluating its oral norovirus pill vaccine candidate in a dose-ranging study in elderly subjects and a boosting regimen study, respectively.

In the dose-ranging, repeat dose trial, the investigational vaccine will be studied participants aged 55 to 80 years old, and it will evaluate the safety and immunogenicity of Vaxarts VP1-based bivalent oral tablet vaccine. Study participants will be randomized into 2 cohorts stratified by age: cohort 1 will receive either a low dose vaccine candidate or placebo . In cohort 2, participants will receive either a high dose vaccine candidate or placebo . The study drug will be an oral tablet administered on days 1 and 29.

The tablet was developed to target the norovirus GI.1 Norwalk and GII.4 Sydney strains, which are the predominant strains affecting humans. Vaxarts oral tablet vaccine candidate is designed to produce antibodies against norovirus locally in the intestine.

Vaxart has also developed an oral vaccine for COVID-19, which is also in clinical trials. Contagion spoke to Vaxart Chief Scientific Officer and Founder Sean Tucker, PhD, last year about the vaccine and the interview can be viewed here.

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Lack Of Immune Correlates Of Protection

The availability of an immune marker able to indicate whether an individual is protected from an infection and related disease can significantly contribute to the development of a vaccine by benefiting evaluation of potential vaccine efficacy. Unfortunately, no reliableimmune correlate of protection from NoV infection and disease valid for all the people has been identified. The use of total serum NoV-specific antibody levels was debated. After infection, NoV-specific antibody concentrations tend to increase in most patients , and in an epidemiological study, serum NoV-specific antibody levels were inversely correlated with protection from NoV AGE development . However, in general, pre-infection antibody levels were not associated with protection .

Further markers of protection might be NoV-specific salivary and fecal IgA and NoV-specific memory IgG cells. In a study, it was found that NoV-specific salivary IgA levels before exposure to NoV were inversely correlated with the severity of AGE. NoV-specific fecal IgA levels before challenge were correlated with a reduction in peak viral load and, when measured 7 days after infection, with a reduced duration of virus shedding. Finally, increased numbers of NoV-specific memory IgG cells were associated with protection from AGE .

Norovirus Acute Gastroenteritis And Socioeconomic Burden

Vaccine developed to protect against norovirus or

The socioeconomic burden of NoV infection is enormous. It has been calculated that in recent years, the global annual mean economic burden of NoV infection was $64.5 billion, of which $4.2 billion were related to the direct health system and $60.3 billion due to societal costs . The costs for illness were higher for people 55 years old and were mainly related to hospitalization. In contrast, societal costs were higher for children < 5 years old, and in this case, parents’ productivity losses played the major role in causing economic problems. Interestingly, high-income countries had the highest global health system costs, highlighting that vaccine prevention of NoV infections can play a relevant role worldwide, although the main reasons can vary according to the geographic area and the age of the involved population.

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The Importance Of Animal Models

Before being accepted for human clinical trials, antivirals, antibodies, and vaccines need to first demonstrate their effectiveness in animal models. The lack of an animal model for studying human norovirus infection and disease has delayed the development of anti-norovirus drugs and vaccines. However, it is now known that gnotobiotic pigs make excellent human norovirus animal models. Gnotobiotic pigs are raised in sterile, germ-free environments so all microbe exposures can be accounted for. This means that, if infected with an organism, its clear that any symptoms that develop will have stemmed from this. These pigs are good candidates as animal models due to their shared similarities with humans. They have similar immune responses as well as virus-binding patterns. This means that disease progression and infection doses determined from these pigs are comparable to what would occur in humans.

Human noroviruses represent a significant burden to global health as well as having an enormous financial cost.

Iu Awarded $12m To Develop First

For Immediate Release

BLOOMINGTON, Ind. — Indiana University will further develop a new technology for a combination oral rotavirus-norovirus vaccine for infants, thanks to a $1.2 million grant from venture capital firm GIVAX Inc.

The technology, first developed by IU Bloomington College of Arts and Sciences biology professor John Patton and graduate student Asha Philip, changes the readily available rotavirus vaccine to also protect against norovirus, a highly contagious virus that can cause severe vomiting and diarrhea in young children.

“We like to think of it as a vaccine for the world,” Patton said. “The children that are the most at risk of dying from these viral infections are in developing countries. We’re modifying a vaccine that is already widely used, giving it greater potential. We think this has strong advantages over other potential options, where you have to use needles and have trained personnel deliver it.”

No vaccine currently exists that can prevent norovirus infection, Patton said. And while most adults recover from viral diarrhea, such illness in young children can lead to hospitalization and life-threatening dehydration. Globally, nearly 100,000 childhood deaths occur each year due to norovirus infection, Patton said.

But norovirus is notoriously difficult to cultivate in the lab, which has been a major impediment to the development of a norovirus vaccine through more traditional routes, Patton said.

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The Path To Vaccine Development

These experiments have shown again that responses to human noroviruses in gnotobiotic pigs are comparable to the responses seen in humans. Disease presents and develops in the same way. Analysing dose-response relationships using various methods leads to a better understanding of how human noroviruses cause disease. Knowing the full extent of how much virus is needed to cause disease and induce symptoms means that an optimal dose can be worked out for testing novel vaccine candidates. The development of vaccines and drugs against human noroviruses is essential to prevent and treat the disease, and reduce the burden it puts on the healthcare sector globally.

How close do you think we are to the successful development of a human norovirus vaccine?



Is There A Treatment

IU researchers developing rotavirus/norovirus oral infant vaccine

Medications are not usually used to treat norovirus. People infected with norovirus usually get better within a few days.

Antibiotics should not be taken for norovirus. Antibiotics only work to fight bacteria and not viruses.

It is important that you drink enough clear fluids, such as water, so you do not get dehydrated. You could also drink fluids such as juices, clear soups, or oral rehydration fluids for vomiting or diarrhea.

See a health care provider if diarrhea or vomiting lasts more than 2 or 3 days, or if dehydration is a concern.

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The Health Effects Of Norovirus

The main symptoms of norovirus illness are:

  • diarrhea
  • muscle aches
  • fatigue

However, for the very young, the elderly, and those with suppressed immune systems, such as those with HIV or AIDS, the disease may be more serious, especially if these people do not drink enough liquids to replace those they lost because of vomiting and diarrhea. They may become dehydrated and need special medical attention to replace the liquids lost from their bodies. This may include hospitalization.

Advances Of Hunov Vaccine Development

HuNoV contains three open reading frames , with ORF2 and ORF3 encoding the major and minor capsid proteins, respectively . The expressed VP1 can self-assemble into virus-like particles , which are virtually indistinguishable from native virus particles . The VP1 capsid monomers can be structurally divided into shell and protruding domains. The S domain forms the structural core, while two P domains wrap around each other to form the base unit dimer . Isolated P dimers still retain functional features of virus particles, including ligand-binding and some antigenic sites . A number of HuNoV vaccines have been designed based on VLPs or P particles due to their structural and functional features . Several HuNoV subunit vaccine candidates based on VLPs and P particles, as shown in Table 1, are in clinical and preclinical trials, under the efforts of many scientists .

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Advances Of In Vivo And In Vitro Hunov Infection Models

The major barrier to HuNoV vaccine development is the lack of robust and reproducible in vivo and in vitro infection models. With the progressive research on the development of HuNoV in vivo and in vitro culture systems, it has been reported that HuNoV can productively infect B cells and human intestinal enteroids in vitro. Regarding animal models, the pigtail macaque is currently the most promising non-human primate infection model for HuNoV . Nevertheless, although many trials of HuNoV infection were performed in animal models, such as adult and suckling mice, kittens, guinea pigs, or rabbits, none were successful . To date, only the recombination activation gene and common gamma chain-deficient BALB/c mouse was shown to support GII HuNoV replication, through the intraperitoneal but not oral route of infection . Zebrafish and pluripotent stem cell-derived organoids were reported as new models for HuNoV replication . These efforts are enabling the development of assays to determine whether antibodies induced by vaccines can abrogate HuNoV infectivity in vitro and in vivo, which would speed the progress of candidate vaccines from preclinical to clinical trials.

Human Norovirus Animal Model Essential For Vaccine Development

Oral Norovirus Vaccine Candidate Posts Positive Results  Precision ...

Human noroviruses are the most common cause of acute gastroenteritis and represent an incredibly high burden on the healthcare sector. Currently no vaccines or drugs exist to prevent or treat the disease. This is in part due to a lack of animal models. Here, Dr Lijuan Yuan and the team at Virginia Polytechnic Institute and State University developed and validated gnotobiotic pigs as an animal model for the human norovirus GII.4/2003 Cin-2. Determining dose-response relationships as well as the median infectious dose, by using different statistical approaches for this virus, means we are one step closer on the path to vaccine development.

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How Can I Reduce The Risk Of Getting Infected From Cleaning Up Vomit Or Diarrhea

If you are cleaning up vomit or diarrhea, follow these tips to reduce the risk of getting infected:

  • Wear disposable gloves. Reusable rubber gloves may be used, but they should be washed after use
  • Use paper towels to soak up excess liquid and put the paper towels and any solid matter directly into a plastic garbage bag
  • Clean the soiled area with soap and hot water. Do not use the same cleaning cloth or sponge to clean other areas of the house as this may spread the virus
  • Disinfect the area that has been washed with a freshly made 1:50 solution of bleach and water. See the How to make a 1:50 solution of bleach and water text box for more information. Household cleaners other than bleach do not work as well for noroviruses
  • Put all cleaning cloths and disposable gloves into a plastic garbage bag and throw out
  • Wash your hands well using soap and water for at least 20 seconds

Human Norovirus Studies Using Gnotobiotic Pigs

Dr Lijuan Yuan and the team at Virginia Polytechnic Institute and State University have been carrying out studies on human noroviruses in gnotobiotic pigs for many years. They established the gnotobiotic pig model of human norovirus infection and diarrhoea for vaccine evaluation. They have also carried out experiments to test changes in infection and immunity in response to various factors. It has been discovered that probiotics provide protection against norovirus while the drug simvastatin enhances the infection. They have also looked into the relationship between noroviruses and the human gut microbiota by transferring human gut bacteria to these gnotobiotic pigs.

Their most recent study, however, focuses on determining the median infectious dose and the median diarrhoea dose with a pandemic strain of human norovirus known as GII.4/2003, or Cin-2. The median diarrhoea dose is the amount of virus that causes 50% of the animals to develop diarrhoea after infection. In order to determine these numbers, the gnotobiotic pigs were separated into seven different groups with each group being inoculated with a different dilution or dose of the virus. Samples were then taken every day from the animals and analysed for viral RNA that had been shed. Diarrhoea symptoms were also assessed daily for seven days.

These experiments have shown that infection and disease caused by human noroviruses in gnotobiotic pigs resemble those seen in humans.

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Global Burden Of Norovirus And Prospects For Vaccine Development

The Bill & Melinda Gates Foundation, in partnership with CDC and the CDC Foundation, have released the report, Global Burden of Norovirus and Prospects for Vaccine Development. The report brings together the work of norovirus researchers and vaccination experts from around the world to describe the burden of norovirus globally and outline further research needed to fill gaps in knowledge and move towards making norovirus vaccines a reality.

Norovirus causes almost one-fifth of all diarrheal disease globally and is estimated to cause up to 200,000 deaths annually. Incidence of norovirus infection is highest in young children, and severe outcomes, including hospitalization and deaths, are common among both children and the elderly. Considering the substantial disease burden and the difficulty in controlling norovirus, vaccination may be the best way to effectively control norovirus in the wider community.

In addition to laying out what is known about the global burden of norovirus and current understanding of infection and immunity, this report outlines the compelling need for a norovirus vaccination program and how technical challenges might be overcome in order to develop a vaccine that will benefit the populations who need it most.

Read the report at .

  • Project Public Health Ready

If You Have Norovirus Illness You Should Drink Plenty Of Liquids To Replace Fluid Lost From Vomiting And Diarrhea This Will Help Prevent Dehydration

Norovirus and the stomach flu are starting to peak again, which is normal during this time of year.

Dehydration can lead to serious problems. Severe dehydration may require hospitalization for treatment with fluids given through your vein .

Watch for signs of dehydration in children who have norovirus illness. Children who are dehydrated may cry with few or no tears and be unusually sleepy or fussy.

If you think you or someone you are caring for is severely dehydrated, call your healthcare provider.

Antibiotic drugs will not help treat norovirus infections because they fight bacteria, not viruses. Learn more about antibiotics.

Drink plenty of liquids to replace fluids that are lost from vomiting and diarrhea. Sports drinks and other drinks without caffeine or alcohol can help with mild dehydration. However, these drinks may not replace important nutrients and minerals. Oral rehydration fluids that you can get over the counter are most helpful for mild dehydration.

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So It Looks Like The Virus And Acts Like The Virus But Its Not And That Is How A Vaccine Designed With Virus

The viral host for this vaccine candidate is called vesicular stomatitis virus , or VSV, a bullet-shaped virus that has been an attractive vector for vaccine designers, Li said. The resulting recombinant viral vector functions as both the vehicle to deliver the vaccine as well as the agent that produces virus-like particles that mimic the human norovirus itself.

In this work, vaccination with the recombinant virus caused the norovirus capsid particles to grow continuously in animals, triggering a specific immune response. When the scientists tested these particles for their antigenic potential to look like foreign intruders in the body, the particles were neutralized by antibodies specifically designed to fight the human norovirus.

So it looks like the virus and acts like the virus, but its not, and that is how a vaccine designed with virus-like particles should function, Li said. The virus-like particles can be continually produced in animals or humans for several weeks and stimulate strong immune responses. Thats the advantage of using VSV.

Li said the VSV-based recombinant is also considered a powerful application because it can essentially be used as a bioreactor to facilitate large-scale production of these specific virus-like particles. In addition, it saves time: The viral vector developed virus-like particles within two days.

Contact: Jianrong Li, 688-5728

Written by Emily Caldwell, 292-8310

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