Tag: vaccine

Rollout of World’s First Malaria Vaccine in Sub-Saharan Africa

Mosquito, a malaria parasite vector
Photo by Егор Камелев on Unsplash

The world’s first malaria vaccine will soon be available across sub-Saharan Africa, according to PATH, partners of the vaccine developers, as positive results from the pioneering jab pile up.

The vaccine, known as RTS,S/AS01E and commercialised under the brand name Mosquirix, targets children as over three quarters of malaria deaths occur in under-five-year olds, according to the latest report from the WHO.

Findings from a WHO pilot held in Ghana, Kenya and Malawi, showed that the pioneering vaccine caused a significant reduction in severe malaria and hospitalisation among vaccinated children.

It means more countries in sub-Saharan Africa will soon receive the vaccine, says John Bawa, Africa lead for vaccine implementation at Program for Appropriate Technology in Health (PATH).

These findings pave the way for an expanded distribution scheme that will see countries like Mozambique, Nigeria and Zambia receive the vaccines, said Bawa during a webinar held in commemoration of World Malaria Day.

“The next is to deploy the vaccine to other endemic countries. Countries that are interested in the vaccine are expected to apply to GAVI from June to September,” he said at the webinar organised by the African Media and Malaria Research Network (AMMREN), PATH and Kintampo Health Research Centre (KHRC).

“Countries like Mozambique, Uganda, Zambia and Nigeria have already written officially to express interest for the vaccine,” Bawa said.

He said malaria vaccine coverage in Malawi was at 88% in 2020 and 93% in 2021. In Ghana, it was 71% in 2020 and 76% in 2021 and in Kenya, it was 69% in 2020 and 83% in 2021.

“These numbers indicate strong community demand and capacity of childhood vaccination platforms to effectively deliver the vaccine to children,” said Bawa.

Currently, 1 million children in Ghana, Kenya and Malawi have received at least one dose of the first malaria vaccine.

These vaccines were distributed in a pilot scheme organized by WHO. The organisation has now recommended the vaccine for use among children in areas with moderate to high transmission rate of malaria.

“This vaccine is not just a scientific breakthrough, it is life-changing for families across Africa. It demonstrates the power of science and innovation for health,” WHO Director-General Dr Tedros Adhanom Ghebreyesus said.

Vaccine procurement

In an arrangement to boost vaccine supply and coverage, GlaxoSmithKline, producers of the RTS,S vaccine, will transfer technology and patent to Bharat Biotech in India to manufacture the vaccines.

The WHO, in a press release, said more than US$155 million has been secured from to support the introduction, procurement and delivery of the malaria vaccine for Gavi-eligible countries in sub-Saharan Africa.

The organisation said it would provide guidance for countries that are considering the use of vaccines for the reduction childhood illnesses and deaths from malaria.

“For some countries, Gavi is paying about 80% [of the] cost of the vaccine, while it is expected that the country’s government would pay the [remaining] 20%,” Bawa said.

Wellington Oyibo, director of the Centre for Malaria Diagnosis, Research, Capacity Building and Policy at the University of Lagos, urged African leaders to ensure that their counterpart funds are available to purchase the vaccine.

He said the Nigerian government and the Prince Ned Nwoko Foundation malaria eradication project have applied to purchase the vaccine for Nigerian children.

Oyibo said while the initial rollout of the vaccine may not go around the country, the Nigerian government selected states with the highest malaria burden to begin with.

Reproduced under a Creative Commons Attribution License.

Source: SciDev.Net

Typhoid Vaccine Safe for Children in Sub-Saharan Africa

Source: Pixabay CC0

typhoid vaccine has proven to be safe and effective for children, which raises hope of fighting the disease in Sub-Saharan Africa, according to a new study conducted in Malawi.

There are more than 1.2 million typhoid cases and 18 703 deaths per year in the region, the researchers wrote. The World Health Organization (WHO) recommended the typhoid conjugate vaccine in 2018 for use in countries where the disease is endemic.

Clinical trials in Malawi showed that a single dose of typhoid conjugate vaccine (the only one licensed for children as young as six months) prevented typhoid in roughly 84% of 14 069 children aged 9 months to 12 years.

“It is a great result for Malawi and for Africa,” says study co-author Melita Gordon, professor of clinical infection, microbiology and immunology at the University of Liverpool and the Malawi-Liverpool-Wellcome Trust Clinical Research Programme.

“We were the only site chosen for the trial on the continent. The other sites were in Nepal and Bangladesh and the results were completely consistent across the three sites.”

Typhoid is endemic in Malawi, which records 400 to 500 cases per 100 000 every year, according to Queen Dube, chief of health services at Malawi’s Ministry of Health.

While typhoid is treatable, it can impair physical and cognitive development in children, affect school attendance and performance, limit productivity and reduce earning potential.

“The existing vaccine could not be used in very young children. In addition, the first line antibiotics have been found to be ineffective against multi-drug resistant strains,” Prof Gordon said. “With this vaccine, we can now expect a reduced typhoid burden.”

After 18 to 24 months of surveillance, the vaccine was found to be safe, with no serious adverse effects on children. It also worked equally well on pre-school aged children.

Prof Gordon explains that the study encountered challenges such as a few children moving out of the research sites within the study period, and COVID-19 forced them to suspend the study for two months.

“However, we eventually managed a good retention rate due to regular text messaging to parents and the hard work of health surveillance assistants in mobilisation activities,” she added.

The efficacy data of the typhoid conjugate vaccine is the first in Africa, according to Gordon, who hopes that other African countries will follow Malawi’s example in planning to roll out the vaccine.

Source: SciDev.Net

Oxford-AstraZeneca Vaccine Tech Tapped to Treat Cancer

Source: National Cancer Institute on Unsplash

The Oxford-AstraZeneca vaccine’s success against SARS-CoV-2 has prompted scientists to develop a vaccine for cancer, using Oxford’s viral vector vaccine technology.

When tested in mouse tumour models, the two-dose therapeutic cancer vaccine increased the numbers of anti-tumour T cells infiltrating the tumours and improved the efficacy of cancer immunotherapy. Compared to immunotherapy alone, combination with the vaccine resulted in a greater reduction in tumour size and improved survival.

The study, which was done by Professor Benoit Van den Eynde’s group at the Ludwig Institute for Cancer Research, University of Oxford in collaboration with co-authors Professor Adrian Hill and Dr Irina Redchenko at the University’s Jenner Institute, has been published in the Journal for ImmunoTherapy of Cancer.

Cancer immunotherapy has improved outcomes for some cancer patients. Anti-PD-1 immunotherapy works by unleashing anti-tumour T cells to allow them to kill cancer cells. However, in the majority of cancer patients, anti-PD-1 therapy is still ineffective .

One reason for the poor efficacy of anti-PD-1 cancer therapy is that some patients have low levels of anti-tumour T cells. Oxford’s vaccine technology generates strong CD8+ T cell responses, which are necessary for strong anti-tumour effects.

The team developed a two-dose therapeutic cancer vaccine with different prime and boost viral vectors, one of which is the same as the vector in the Oxford-AstraZeneca COVID vaccine. In order to create a vaccine treatment that specifically targets cancer cells, the vaccine was designed to target two MAGE-type proteins found on the surface of many types of cancer cells.

Preclinical experiments in mouse tumour models demonstrated that the cancer vaccine increased the levels of tumour-infiltrating CD8+ T cells and enhanced the response to anti-PD-1 immunotherapy. The combined vaccine and anti-PD-1 treatment resulted in a greater reduction in tumour size and improved the survival of the mice compared to anti-PD-1 therapy alone.

Benoit Van den Eynde, Professor of Tumour Immunology at the University of Oxford, said: “We knew from our previous research that MAGE-type proteins act like red flags on the surface of cancer cells to attract immune cells that destroy tumours.

“MAGE proteins have an advantage over other cancer antigens as vaccine targets since they are present on a wide range of tumour types. This broadens the potential benefit of this approach to people with many different types of cancer.

“Importantly for target specificity, MAGE-type antigens are not present on the surface of normal tissues, which reduces the risk of side-effects caused by the immune system attacking healthy cells.”

Human trials in 80 patients with non-small cell lung cancer will be launched later this year.

Adrian Hill, Lakshmi Mittal and Family Professorship of Vaccinology and Director of the Jenner Institute, University of Oxford, said: “This new vaccine platform has the potential to revolutionise cancer treatment. The forthcoming trial in non-small cell lung cancer follows a Phase 2a trial of a similar cancer vaccine in prostate cancer undertaken by the University of Oxford that is showing promising results.

“Our cancer vaccines elicit strong CD8+ T cell responses that infiltrate tumours and show great potential in enhancing the efficacy of immune checkpoint blockade therapy and improving outcomes for patients with cancer.”

Source: Oxford University

Nasal COVID Vaccines Will Greatly Reduce Transmission

Source: CDC on Unsplash

Though great progress has been made in developing intramuscular COVID vaccines, as yet nothing provides mucosal immunity in the nose, the first barrier against the virus encounters before it travels down to the lungs.

In terms of both immune cell deployment and immunoglobulin production, the mucosal immune system is by far the largest component of the entire immune system, having evolved to provide protection at the main sites of infectious threat: the mucosae.

In iScience, Navin Varadarajan, Professor of Chemical and Biomolecular Engineering, and colleagues, report the development of an intranasal subunit vaccine that provides durable local immunity against inhaled pathogens.

“Mucosal vaccination can stimulate both systemic and mucosal immunity and has the advantage of being a non-invasive procedure suitable for immunization of large populations,” explained Prof Varadarajan. “However, mucosal vaccination has been hampered by the lack of efficient delivery of the antigen and the need for appropriate adjuvants that can stimulate a robust immune response without toxicity.”

To get around this, Prof Varadarajan worked with Xinli Liu, associate professor of pharmaceutics, and an expert in nanoparticle delivery. Prof Liu’s team packaged the agonist of the stimulator of interferon genes (STING) inside liposomal particles to create an adjuvant called NanoSTING. 

“NanoSTING has a small particle size around 100 nanometres, which exhibits significantly different physical and chemical properties to the conventional adjuvant,” said Prof Liu.

“We used NanoSTING as the adjuvant for intranasal vaccination and single-cell RNA-sequencing to confirm the nasal-associated lymphoid tissue as an inductive site upon vaccination. Our results show that the candidate vaccine formulation is safe, produces rapid immune responses—within seven days—and elicits comprehensive immunity against SARS-CoV-2,” said Prof Varadarajan.

Intramuscular vaccines have a fundamental limitation in that they are not designed to elicit mucosal immunity. As shown in previous work with respiratory pathogens like influenza, sterilising immunity to virus reinfection requires adaptive immune responses in the respiratory system.

The nasal vaccine will also help the equitable global distribution of vaccines, according to the researchers. Many smaller countries have only vaccinated a small percentage of their population, and outbreaks continue. These outbreaks and viral spread are known to facilitate viral evolution, ultimately leading to decreased efficacy of all vaccines.

“Equitable distribution requires vaccines that are stable and that can be shipped easily. As we have shown, each of our components, the protein (lyophilised) and the adjuvant (NanoSTING) are stable for over 11 months and can be stored and shipped without the need for freezing,” said Prof Varadarajan.

Source: University of Houston

A Step Towards an Asthma Vaccine

Researchers have tested a newly developed vaccine that could confer long-term protection against allergic asthma, reducing the severity of its symptoms. 

Their research in animals has been published in the journal Nature Communications.

Asthma affects 340 million worldwide. It is a chronic disease of the air passages characterised by inflammation and narrowing of the airways in response to allergens such as dust mites. Symptoms of asthma include shortness of breath, cough, and wheezing. 

Exposure to dust mites and other allergens leads to the production of antibodies called immunoglobulin E (IgE) and type 2 cytokines (such as interleukin-4 (IL-4) and IL-13) in the airways. This leads to a cascade of reactions resulting in hyperresponsiveness of the respiratory tract, excessive mucus production, and eosinophilia (when there are too many eosinophils, a type of white blood cell, in the airways).

Currently, inhaled corticosteroids are the gold standard for controlling asthma — but in the case of severe asthma, this treatment is not enough. Then, it is necessary to use therapeutic monoclonal antibodies that target IgE or the IL-4 and IL-13 pathways. These are costly treatments, however, requiring long-term or even lifelong administration of injections.

To solve this, the researchers developed a conjugate vaccine, called a kinoid, by coupling the recombinant cytokines IL-4 and IL-13 with a carrier protein called CRM197 (a non-pathogenic mutated form of the diphtheria toxin, used in many conjugate vaccines).

The preclinical results from animal models demonstrate that this vaccine induces the sustained production of antibodies specifically directed against IL-4 and IL-13. The vaccine was so effective that six weeks after the first injection of the conjugate vaccine, 90% of the mice presented high levels of antibodies. Over one year after primary immunisation, 60% of them still had antibodies capable of neutralising IL-4 and IL-13 activity.

The vaccine was also shown to strongly reduce levels of IgE, eosinophilia, mucus production and airway hyperresponsiveness in a model of dust mite allergic asthma. This study therefore suggests both the prophylactic and therapeutic efficacy of the vaccine in this model of asthma and no adverse effects were observed in the animals. The next step for the researchers will be to test these findings in a clinical trial setting.

Source: Medical Xpress

Journal information: Eva Conde et al, Dual vaccination against IL-4 and IL-13 protects against chronic allergic asthma in mice, Nature Communications (2021). DOI: 10.1038/s41467-021-22834-5

TB Vaccine Shown to Protect Against Common Infections

The tuberculosis (TB) vaccine Bacillus Calmette-Guerin (BCG) could protect newborns against a variety of common infections, such as upper respiratory tract infections, chest infections, and diarrhoea, according to a new study from the London School of Hygiene and Tropical Medicine (LSHTM).

It has been known that BCG protects against diseases other than TB, offering protection against non-tuberculous mycobacteria infection like leprosy and Buruli ulcer. It is also used in the treatment of superficial carcinoma of the bladder.

However, this is the first research to rigorously investigate the full range. The results suggest that vaccinating all babies with BCG on their day of birth could save lives by reducing neonatal infections in areas with high rates of infectious disease.

The study involved a randomised control trial of 560 newborns in Uganda, who were monitored for a range of illnesses. After six weeks, infection rates from any disease were 25% lower in the group that received the vaccine at birth, compared to the group that had not yet received the vaccination. The most protected appeared to be vulnerable groups such as low birth weight babies, and boys. Importantly, BCG appeared to protect against even severe infections.

Sarah Prentice, the lead author from LSHTM, said: “Nearly a million babies die every year of common infections so we urgently need better ways to protect them. Our research suggests that ensuring that BCG is given at birth could make a big difference in low-income countries, potentially saving many lives.”

The newborns were randomly assigned to receive BCG either at birth or at six weeks of age. They were followed-up by doctors, blinded to the intervention, for 10 weeks, who looked for any type of illness or infection.

The research team then compared how often infants in the two groups presented to doctors with infections of any kind, except TB, to see whether having BCG made a difference. They also took blood samples from both groups, to look at differences in their innate immune system, the body’s first line of defense against infections.

Infants vaccinated with BCG at birth presented to doctors with any kind of infection 25% less often than infants who had not. BCG seemed to protect against all kinds of infections, such as common colds, chest infections, and skin infections.

After the delayed group had been vaccinated, the rates of infection were identical between the two groups: the delayed group’s immunity ‘brought up to speed’ when they received BCG.

Study co-author Prof Hazel Dockrell, LSHTM, said: “It’s very exciting to think that BCG vaccination might help keep newborns safe against other dangerous infections, in addition to providing protection against TB. Although BCG is recommended at birth in many countries, it is often delayed due to logistical difficulties. Ensuring that the vaccine is given on day one, in areas with high rates of infectious disease, could have a major impact on infections and deaths in the newborn period.”

Though the study could not definitely determine whether the BCG vaccine was responsible for the lowered rate of infections, there is nonetheless great interest in applying the vaccine as a protection for novel disease outbreaks, such as COVID or Ebola, before a specific vaccine can be developed.

Dr Prentice said, “Since the findings show that BCG seems to offer wider protection against a range of infections, our study also raises hopes it might be useful in protecting the general population against COVID-19 and future pandemics – though we will need to see the results of other, more specific studies to know for sure.”

Source: News-Medical.Net

Journal information: Prentice, S., et al. (2021) BCG-induced non-specific effects on heterologous infectious disease in Ugandan neonates: an investigator-blind randomised controlled trial. The Lancet Infectious Diseases. doi.org/10.1016/S1473-3099(20)30653-8.

Ebola Vaccine Stockpile Being Created

The International Coordinating Group (ICG) announced on Monday that it was creating a stockpile of the Ebola vaccine in Switzerland, to help contain future outbreaks. Between 2014 and 2016, the haemorrhagic fever claimed 11 300 lives, with a fatality rate of 90%.

The single dose Ebola vaccine was trialled with 350 000 in Guinea and in the 2018-2020 DRC outbreak under “compassionate use”. The vaccine was jointly developed by the World Health Organization (WHO), UNICEF, the International Federation of Red Cross and Red Crescent Societies (IFRC) and Médecins Sans Frontières (MSF), with Gavi, the Vaccine Alliance, providing financial support.Countries requesting a vaccine will be able to receive a response in 48 hours, with a goal for a seven day delivery time.Unlike COVID, Ebola is a rare and unpredictable disease, and thus there is the need to create a reserve for the vaccine as opposed there being a “natural market” for it.

“We are proud to be part of this unprecedented effort to help bring potential Ebola outbreaks quickly under control,” said Henrietta Fore, UNICEF executive director, in a press release, saying that when it comes to dealing with disease outbreaks, “preparedness is key.”

She said the vaccine stash is a “remarkable achievement” that will allow vaccines to be delivered to those who need them in a timely manner. 
Assembling the required 500 000 doses for the stockpile will take some to three years, with 6890 doses currently available for outbreak response. The WHO, UNICEF, Gavi, and vaccine manufacturers are in the meantime are ready to escalate production if needed.

Source: Voice of America News

SA Scientists Warn Local COVID Variant May Resist Vaccine

South African scientists have said that there is a “reasonable concern” that the South African strain of SARS-CoV-2 may have greater resistance to current vaccines, and underscored the need for global vaccination.

Speaking to the BBC,  Prof Shabir Madhi, who has led vaccine trials in South Africa, explained, “It’s a theoretical concern. A reasonable concern… that the South African variant might be more resistant.” 

The South African variant has mutated far more than the UK variant, raising the possibility that it may be able to evade the antibodies that typically fight coronavirus.

Prof Helen Rees, a vaccine expert at Wits University, said, “Fortunately, should further modifications of the vaccine be required to address the new variants, some of the vaccine technologies under development could allow this to be done relatively rapidly.”

South African scientists recently pushed back against the notions that the SA variant was more transmissible than the UK one, or that it is more deadly. Explaining the reason for the flight restrictions from South Africa, UK Health Secretary Matt Hancock has stated that he believed it was more infectious than the UK variant, saying “This is a very, very significant problem […] and it’s even more of a problem than the UK new variant.”
The UK variant has a “transmission advantage” of 0.4 to 0.7, leading to reproduction numbers of 1.4 to 1.8.Prof Madhi said laboratory tests would determine whether current vaccines would be effective against this variant in a few weeks.

Source: BBC News 

COVID Vaccines May Lose Potency as Virus Evolves

Looking to a time beyond the development of COVID vaccines, researchers are attempting to determine how long the SARS-CoV-2 virus will take to develop resistance to those vaccines.

David Kennedy, assistant professor of biology at Pennsylvania State University said, “A COVID-19 vaccine is urgently needed to save lives and help society return to its pre-pandemic normal,” said David Kennedy, assistant professor of biology. “As we have seen with other diseases, such as pneumonia, the evolution of resistance can quickly render vaccines ineffective. By learning from these previous challenges and by implementing this knowledge during vaccine design, we may be able to maximise the long-term impact of COVID-19 vaccines.”

The researchers recommend that vaccines be designed to create multiple immune responses, making it harder for the vaccine to survive the immune system’s attack, much the way multiple antibiotics are used to suppress bacterial infections, by forcing the virus to have multiple mutations to survive.

Strongly suppressing virus transmission through the host is key to minimising the amount of mutation and thereby the lifespan of the vaccine’s  effectiveness.

“According to the World Health Organization, at least 198 COVID-19 vaccines are in the development pipeline, with 44 currently undergoing clinical evaluation,” said Kennedy. “We suggest that the risk of resistance be used to prioritise investment among otherwise similarly promising vaccine candidates.”

Source: SciTech Daily