Category: COVID

Categories : COVIDTags :

Time is Running out to Develop a Paxlovid Alternative

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Researchers from Rutgers University in the U.S. believe that they are ahead in a race to find an oral COVID-19 treatment to supplement or replace the antiviral Paxlovid. Their report, published in Science, shows that an alternative medication, a viral papain-like protease inhibitor, inhibits disease progression in animals while also possessing an important advantage over Paxlovid – fewer prescription drug contraindications.

“COVID-19 remains the nation’s third leading cause of death, so there’s already a massive need for additional treatment options,” said Jun Wang, senior author of the study and associate professor at Rutgers. “That need will grow more urgent when, inevitably, COVID-19 mutates in ways that prevent Paxlovid from working.”

The Rutgers team hoped to make a drug that interfered with viral papain-like protease (PLpro), a protein that performs important functions in all known strains of COVID-19.

Creating such a drug required detailed information about PLpro’s structure, which Wang’s team got from the Arnold Lab at Rutgers’ Center for Advanced Biotechnology and Medicine (CABM).

Precise knowledge of PLpro’s structure enabled Wang’s team to design and synthesise 85 drug candidates that would bond to – and interfere with – this vital protein.

“The PLpro crystal structures showed an unexpected arrangement of how the drug candidate molecules bind to its protein target, leading to innovative design ideas implemented by professor Wang’s medicinal chemistry team,” said Eddy Arnold, who is a professor at CABM.

Laboratory testing established that the most effective of those drug candidates, a compound dubbed Jun12682, inhibited several strains of the SARS-CoV-2 virus, including strains that resist treatment with Paxlovid.

Oral treatment with Jun12682 on SARS-CoV-2-infected mice was shown to reduce viral lung loads and lesions while improving survival rates.

“Our treatment was about as effective in mice as Paxlovid was in its initial animal tests,” said Wang, who added the experimental drug appears to have at least one major advantage over the older drug.

“Paxlovid interferes with many prescription medications, and most people who face the highest risk of severe COVID-19 take other prescription medicines, so it’s a real problem,” Wang said.

“We tested our candidate Jun12682 against major drug-metabolising enzymes and saw no evidence that it would interfere with other medications.”

Source: Rutgers University

Categories : COVID Ethics and LawTags :

Pretoria High Court Judgement On COVID-19 Vaccinations

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On 05 January 2023, the COVID Care Alliance NPC and other applicants brought an urgent court application against the South African Health Products Regulatory Authority (SAHPRA), including the President of the Republic of South Africa and others to prevent people from being vaccinated.

The applicants wanted the court to order that all COVID-19 vaccines programs must be stopped and that all COVID-19 vaccination sections in healthcare facilities in South Africa must be closed, and the effective withdrawal from circulation of the vaccines. The applicants also sought an order interdicting the approval of vaccines for emergency authorisation or registration.

On 27 February 2024, the Pretoria High Court dismissed with costs an application filed by the applicants on the grounds that the applicants do not have the right to prevent others, who do not share in their beliefs or opinions, from being vaccinated.

SAHPRA submitted evidence to the Court to show that the applicants’ attempt to prevent government from using vaccines to address the COVID-19 pandemic was misguided, and the applicants heavily relied on hearsay and speculation, as well as supported their arguments with the opinion of persons who were not experts.

Source: SAHPRA

Categories : COVID VaccinesTags :

Hypervaccination: Researchers Investigate a Man who Received 217 COVID Shots

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Researchers in Germany find no negative effects on immune system

Photo by Gustavo Fring

Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen have examined a man who has received more than 200 vaccinations against COVID. They learned of his case via newspaper reports.

Until now, it has been unclear what effects hypervaccination such as this would have on the immune system. Some scientists were of the opinion that immune cells would become less effective after becoming used to the antigens. This proved not to be the case in the individual in question: his immune system is fully functional. Certain immune cells and antibodies against SARS-CoV-2 are even present in considerably higher concentrations than is the case with people who have only received three vaccinations. The results have been published in the journal Lancet Infectious Diseases.

More than 60 million people in Germany have been vaccinated against SARS-Coronavirus 2, the majority of them several times. The man who has now been examined by researchers at FAU claims to have received 217 vaccinations for private reasons. There is official confirmation for 134 of these vaccinations.

“We learned about his case via newspaper articles,” explains Privatdozent Dr Kilian Schober from the Institute of Microbiology – Clinical Microbiology, Immunology and Hygiene (director Prof Dr Christian Bogdan). “We then contacted him and invited him to undergo various tests in Erlangen. He was very interested in doing so.” Schober and his colleagues wanted to know what consequences hypervaccination such as this would have. How does it alter the immune response?

As a rule, vaccinations contain parts of the pathogen or a type of construction plan that the vaccinated person’s cells can use to produce these pathogenic components themselves. Thanks to these antigens, the immune system learns to recognize the real pathogen in the event of a later infection. It can then react more rapidly and forcibly. But what happens if the body’s immune system is exposed extremely often to a specific antigen?

“That may be the case in a chronic infection such as HIV or Hepatitis B, that has regular flare-ups,” explains Schober. “There is an indication that certain types of immune cells, known as T-cells, then become fatigued, leading to them releasing fewer pro-inflammatory messenger substances.” This and other effects triggered by the cells becoming used to the antigens can weaken the immune system. The immune system is then no longer able to combat the pathogen so effectively.

Blood samples from several years investigated

The current study, which also involved researchers from Munich and Vienna, does not deliver any indication that this is the case, however. “The individual has undergone various blood tests over recent years;” explains Schober. “He gave us his permission to assess the results of these analyses. In some cases, samples had been frozen, and we were able to investigate these ourselves. We were also able to take blood samples ourselves when the man received a further vaccination during the study at his own insistence. We were able to use these samples to determine exactly how the immune system reacts to the vaccination.”

The results showed that the individual has large numbers of T-effector cells against SARS-CoV-2. These act as the body’s own soldiers that fight against the virus. The test person even had more of these compared to the control group of people who have received three vaccinations. The researchers did not perceive any fatigue in these effector cells, they were similarly effective as those in the control group who had received the normal number of vaccinations.

Memory T cells are another aspect the researchers explored. These are cells at a preliminary stage, before effector cells. Similar to stem cells, these cells can replenish numbers of suitable effector cells. “The number of memory cells was just as high in our test case as in the control group,” explains Katharina Kocher, one of the leading authors of the study. “Over all, we did not find any indication for a weaker immune response, rather the contrary.”  In addition, even the 217th vaccination that the man received during the study still had an effect: the number of antibodies against SARS-CoV-2 increased significantly as a result.

Immune system remains active against other pathogens

Further tests indicated that there was no change to the immune system’s effectiveness against other pathogens. It therefore appears to be the case that the hypervaccination has not damaged the immune system as such. “Our test case was vaccinated with a total of eight different vaccines, including different available mRNA vaccines,” stated Dr Kilian Schober. “The observation that no noticeable side effects were triggered in spite of this extraordinary hypervaccination indicates that the drugs have a good degree of tolerability.”

However, this is one individual case. The results are not sufficient for making far-reaching conclusions let alone recommendations for the general public. “Current research indicates that a three dose vaccination, coupled with regular top-up vaccines for vulnerable groups, remains the favoured approach. There is no indication that more vaccines are required.”

Source: Friedrich–Alexander University Erlangen–Nurnberg

Categories : COVID VaccinesTags :

COVID Vaccination and Antibody Responses Found to be Long-lasting

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A long-term analysis conducted by leading microbiologists at the Icahn School of Medicine at Mount Sinai reveals that antibody responses induced by COVID vaccines are long-lasting. The study results, published online in the journal Immunity, challenge the idea that mRNA-based vaccine immunity wanes quickly.

The emergence of SARS-CoV-2 in late 2019 sparked the global pandemic that is now in its fifth year. Vaccines that were developed at record speed have saved millions of lives. However, the emergence of SARS-CoV-2 variants and waning immunity have decreased the effectiveness of the vaccines against symptomatic disease. The common perception now is that mRNA-based vaccine-induced immunity wanes quickly. However, this assumption is largely based on data from short-term studies that include a very limited number of data points following peak responses.

The Mount Sinai research team’s analysis of more than 8000 samples collected over a three-year period in New York City examined how antibody responses to the virus’s spike protein changed after infections, during the primary immunisation series, during monovalent and bivalent booster vaccination, and during breakthrough infections.

They found that upon primary immunisation, participants with pre-existing immunity (those who had previously been infected with the virus) mounted higher antibody responses faster and achieved higher steady-state antibody titres than individuals who had not been previously infected. The waning of antibody response was characterised by two phases: an initial rapid decay from the strong peak after vaccination, followed by a stabilisation phase with very slow decay, suggesting that antibody levels were very long-lasting. Booster vaccination equalised the differences in antibody concentration between participants with and without pre-existing immunity. Breakthrough infections increased antibodies to similar levels as an additional vaccine dose in individuals who had not previously been infected.

This investigation represents one of the most extensive and in-depth assessments of the longevity of SARS-CoV-2 immune responses to date. Its major conclusion is that changes in the virus that allow it to evade immunity, rather than waning immunity, are the major reason for breakthrough infections.

“Ours is one of the longest-running COVID-19 studies out there,” said Viviana Simon, MD, PhD, Professor of Microbiology, Medicine and Pathology, Molecular and Cell-Based Medicine, at Icahn Mount Sinai and lead author of the paper. “Following the same group of people monthly over time is rare and powerful because you can compare immune responses on an individual level. SARS-CoV-2 continues to evolve, so this research is important to provide an understanding about the impact of new variants and new vaccine doses on a healthy immune system, and to guide all of us to make the best choices to maintain protection against the virus that continues to circulate in our communities.”

This in-depth analysis was made possible through the Protection Associated with Rapid Immunity to SARS-CoV-2 (PARIS) study, an observational, longitudinal cohort of health care workers of the Mount Sinai Health System that was initiated in April 2020. At that time, the densely populated New York metropolitan area was hit with an exponential increase in severe SARS-CoV-2 infections, and essential workers in the health care system were at high risk for infection. In response to the crisis, a team of leading virologists, physician-scientists, and pathologists at Mount Sinai established a specific and sensitive SARS-CoV-2 binding enzyme-linked immunosorbent assay to accurately measure the SARS-CoV-2 antibody titres. This test was used to measure immune responses in the PARIS cohort in order to determine how quickly the antibody defences were mounted and much these changed over the months and years of follow up.

In addition to showing the impact on a person’s individual antibody response to vaccines based on the type of vaccine received and whether or not they were infected before receiving the first dose, the PARIS study made possible the development of a mathematical model that can be used to predict and characterize antibody responses of both individual people and populations.

“People have pandemic fatigue and vaccine uptake has slowed, especially after the vaccines started to be charged to insurance,” said Komal Srivastava, MS, Director of Strategy and Operation of the Mount Sinai Center for Vaccine Research and Pandemic Preparedness and co-first author of the paper. “We were pleasantly surprised to see that the booster doses promoted a large antibody response regardless of a person’s personal infection history, so we are hopeful that our study findings will encourage people to get their vaccine boosters when eligible and to stay engaged in research. Our work also showcases the impact of viral evolution over time and why it’s critical to keep studies like this going, despite the pandemic fatigue.”

According to the research team, the PARIS model has broad applications for studying the kinetics of antibodies produced to different COVID vaccines in diverse populations. They stress much more work remains to analyse side effects, applications of the antibody model and continued research about new vaccines and viral variants.

“This study adds an essential piece of data to understand the intricate immune response elicited by SARS-CoV-2 infection and COVID-19 vaccination,” says Juan Manuel Carreno Quiroz, PhD, Assistant Professor in the Department of Microbiology and co-first author of the paper. “In light of the emerging viral variants, which predominantly induce a cross-reactive antibody response against the spike protein, it will be exciting to characterise in depth the role of these antibodies – in particular the non-neutralising ones – in protection against the most recent circulating viral variants. Likewise, monitoring the induction of variant-specific antibodies after multiple exposures by breakthrough infections and by administration of updated COVID-19 vaccines, such as the XBB.1.5 monovalent booster, will be key to understand the evolution of the antibody response over time.”

Source: The Mount Sinai Hospital / Mount Sinai School of Medicine

Categories : COVID Respiratory DiseasesTags :

New T Cell ‘Rescue’ Therapy Promising for ARDS

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Promising trial results indicate that a new type of cell therapy could improve the prognosis of those who are critically ill with acute respiratory distress syndrome (ARDS) resulting from severe COVID.

Published in the journal Nature Communications, Professor Justin Stebbing of Anglia Ruskin University (ARU) is the joint senior author of the new study investigating the use of agenT-797, MiNK Therapeutic’s allogeneic, unmodified invariant natural killer T (iNKT) cell therapy.

The iNKT cell therapy has the effect of rescuing exhausted T cells and prompting an anti-inflammatory cytokine response, potentially activating anti-viral immunity to help these patients fight infection as well as to reduce severe, pathogenic inflammation of the lung.

The new research was carried out at three medical centres and found that agenT-797, which is also under investigation in cancer trials, could be manufactured rapidly, had a tolerable safety profile, and appeared to have a positive effect on mortality among critically unwell Covid-19 ARDS patients receiving intensive care.

The exploratory trial included 20 mechanically ventilated patients with severe ARDS secondary to Covid-19. Of the 20 patients in the trial, 14 survived (70%) at 30 days (compared to a control group of 10%), and there was an 80% lower occurrence of bacterial pneumonia amongst those who received the highest dosage of agenT-797, compared to those who received fewer cells.

Twenty-one patients were treated overall (the main trial, plus one under compassionate use), which included five who were also receiving veno-venous extracorporeal membrane oxygenation (VV-ECMO), known as ‘the most aggressive salvage therapy’ for critically ill patients with ARDS.

In VV-ECMO, deoxygenated blood is pumped through a membrane lung and returned to the body via a cannula. This trial is believed to be the first immune cell therapy of any type to be used in critically unwell patients undergoing VV-ECMO.

Survival of the VV-ECMO cohort was 80% after 30 and 90 days, and 60% after 120 days. This compares favourably to overall survival of 51% for patients with Covid-19 who were treated with just VV-ECMO at the same institution, during the same timeframe.

Joint senior author Justin Stebbing, Professor of Biomedical Sciences at Anglia Ruskin University (ARU) in Cambridge, England, said: “During this small, exploratory study we observed that MiNK’s iNKT cell treatment, which is also being advanced for people with cancer, triggered an anti-inflammatory response in ARDS patients.

“Despite a poor prognosis, critically ill patients treated with this therapy showed favourable mortality rates and those treated at the highest dose also had reduced rates of pneumonia, underscoring the potential application of iNKT cells, and agenT-797 in particular, in treating viral diseases and infections more broadly.

Source: Anglia Ruskin University

Categories : COVID Immune SystemTags :

COVID did not get Weaker – Our Immune Systems got Stronger, Large Scale Study Suggests

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Researchers have shown that the reduced mortality from COVID is not necessarily due to the fact that later variants, such as Omicron, have been less severe. Rather, the reduced mortality seems to be due to several other factors, such as immunity from previous vaccinations and previous infections. The study is published in the latest issue of Lancet Regional Health Europe.

The researchers at Karolinska Institutet, together with partners in the EuCARE project, conducted a study using patient data from more than 38 500 hospitalised patients with COVID, from the start of the pandemic to October 2022. The data comes from hospitals in ten countries, including two outside Europe.

The data showed that in-hospital mortality decreased as the pandemic progressed, especially since Omicron became the dominant variant. However, when the researchers modelled the mortality rates for different variants (pre-Alpha, Alpha, Delta and Omicron) and took into account factors such as age, gender, comorbidity, vaccination status and time period, they saw far fewer differences and weaker associations. They also saw differences between age groups, highlighting the importance of conducting separate analyses for different age groups. 

“Overall, our findings suggest that the observed reduction in mortality during the pandemic is due to multiple factors such as immunity from vaccination and previous infections, and not necessarily tangible differences in inherent severity,” says Pontus Hedberg, first author of the study. 

Omicron variant no less severe 

Understanding the disease course and outcomes of patients hospitalised with COVID during the pandemic is important to guide clinical practice and to understand and plan future resource use for COVID. A particularly interesting finding is that the inherent severity of Omicron has not necessarily been significantly reduced, but that other factors are behind the reduction in mortality. 

“The fact that Omicron can cause severe disease was seen in Hong Kong, for example, where the population had low immunity from previous infections and low vaccination coverage. In Hong Kong there was a relatively high mortality from Omicron,” says Pontus Hedberg. 

Highlights the importance of protecting the elderly and those with underlying diseases

The main applications of the study results going forward are the continued need to protect the elderly and patients with other underlying disease from severe disease outcomes through vaccination against COVID, even though new virus variants may appear less virulent. The results are also important for understanding trends in mortality in hospitalised patients with COVID and thus planning for resource use in hospital care.

Larger multinational collaborative projects like this are of great value to increase the generalisability of studies and not least to promote international collaboration also for future pandemic or epidemic scenarios.

Source: Karolinska Institutet

Categories : COVID Immune SystemTags :

Overactive Complement System Causes Long Covid

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A new study from the University of Zurich (UZH) has revealed that the complement system plays an important role in Long Covid, a common sequela of SARS-CoV-2 infection. The findings, published in Science, show that the complement system ends up damaging tissue and blood cells even after the original infection has ended.

A significant proportion of individuals infected with SARS-CoV-2 develop long-lasting symptoms with a wide range of manifestations. The causes and disease mechanisms of Long Covid are still unknown, and there are no diagnostic tests or targeted treatments.

Part of the immune system active for too long

A team of researchers led by Onur Boyman, professor of immunology at UZH and Director of the Department of Immunology at the University Hospital Zurich (USZ), has implicated the complement system. It is part of the innate immune system and normally helps to fight infections and eliminate damaged and infected body cells.

“In patients with Long Covid, the complement system no longer returns to its basal state, but remains activated and, thus, also damages healthy body cells,” says Boyman.

Continued activation of complement system damages tissue and blood cells

The researchers followed 113 COVID patients for up to one year after their acute SARS-CoV-2 infection and compared them with 39 healthy controls.

After six months, 40 patients had active Long Covid disease.

More than 6500 proteins in the blood of the study participants were analysed both during the acute infection and six months later.

“The analyses of which proteins were altered in Long Covid confirmed the excessive activity of the complement system. Patients with active Long Covid disease also had elevated blood levels indicating damage to various body cells, including red blood cells, platelets and blood vessels,” explains Carlo Cervia-Hasler, a postdoctoral researcher in Boyman’s team and first author of the study.

Bioinformatics recognises protein patterns

The measurable changes in blood proteins in active Long Covid indicate an interaction between proteins of the complement system, which are involved in blood clotting and the repair of tissue damage and inflammation.

In contrast, the blood levels of Long Covid patients who recovered from the disease returned to normal within six months.

Active Long Covid is therefore characterised by the protein pattern in the blood.

The blood markers were discovered using bioinformatics methods in collaboration with Karsten Borgwardt during his time as a professor at ETH Zurich.

“Our work not only lays the foundation for better diagnosis, but also supports clinical research into substances that could be used to regulate the complement system. This opens up new avenues for the development of more targeted therapies for patients with Long Covid,” Onur Boyman said.

Source: University of Zurich

Categories : COVID VaccinesTags :

A Universal Coronavirus Vaccine could Save Millions of Lives in a Future Pandemic

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What if in the years prior to the COVID pandemic, scientists had developed a universal coronavirus vaccine, one that targets parts common to coronaviruses, offering some protection against all strains? Would it have been of help during the pandemic?

A new study suggests if such a vaccine were available at the start of the pandemic, it could have saved millions of lives, prevented suffering, and saved billions of dollars in direct medical and other costs until the strain-specific (ie, SARS-CoV-2) vaccine went through the entire development, testing, and emergency use authorisation process that lasted 10 months.

In this study, published in The Lancet’s eClinicalMedicine, researchers show that having a universal vaccine at the start of the pandemic would have had substantial health and economic benefits under almost all scenarios tested.

In order to determine the value of investing in developing and stockpiling a universal coronavirus vaccine, the team developed a computational model that simulated the entire US population, the introduction and spread of a novel coronavirus like SARS-CoV-2 in 2020 and the resulting health (eg, infections, hospitalisations) and economic (eg, direct medical costs, productivity losses) outcomes.

The experiments simulated what would happen if a universal coronavirus vaccine was available at the start of the COVID pandemic.

Vaccinating with a universal coronavirus vaccine as a standalone intervention (e.g., no face mask use or social distancing) was cost-saving even when its efficacy was as low as 10% and only 10% of the U.S. population received the vaccine.

For example, when a universal coronavirus vaccine has 10% efficacy, vaccinating a quarter of the U.S. population within two months of the start of the pandemic averts an average of 14.6 million infections and saves over $27 billion in direct medical costs.

Such low vaccine coverage at the start of the pandemic could occur if a vaccine were only made available to certain high-risk subpopulations (eg, 65 years and older, the immunocompromised, frontline workers), similar to the approach when mRNA vaccines became available in December 2020.

“COVID-19 was the third major and serious coronavirus epidemic or pandemic following SARS in 2002 and MERS in 2012, thus, we should anticipate a fourth coronavirus outbreak within the next decade or so,” says Peter J. Hotez, MD, PhD, dean of Baylor’s National School of Tropical Medicine and co-director of the Texas Children’s Hospital Center for Vaccine Development.

“A universal vaccine is cost-effective and cost-saving and a priority for advancement.”

A universal coronavirus vaccine was also shown to be highly cost-effective even if a more specific and more efficacious vaccine came to market.

For example, the study shows if it takes four months or longer for a strain-specific vaccine to reach the market, using a universal vaccine was still cost cost-saving.

In a scenario where a strain-specific vaccine has 90% efficacy but is unavailable for two months after the start of the pandemic, the results from the model show that vaccinating only 10% of the population with a universal vaccine that has 10% efficacy at the start of the pandemic can save over $2 billion in societal costs (eg, direct medical costs and productivity losses from absenteeism). Given the time required to develop a strain-specific vaccine during a pandemic to match circulating strains of the virus, this highlights the importance of having a universal vaccine readily available as a stopgap.

“Our study shows the importance of giving as many people as possible in a population at least some degree of immune protection as soon as possible,” explains Bruce Y. Lee, MD, MBA, executive director of PHICOR and professor at CUNY SPH.

“Having a universal vaccine developed, stockpiled, and ready to go in the event of a pandemic could be a game-changer even if a more specific vaccine could be developed three to four months later.”

Generally, results from the model found that a universal vaccine would end up saving money if the cost to get a person vaccinated (eg, cost of the vaccine itself, distribution, administration, storage, research, and development) is as high as $10 390 from a societal perspective.

Source: CUNY Graduate School of Public Health and Health Policy

Categories : COVIDTags :

Paxlovid does not Reduce Risk of Long COVID, Study Finds

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A recent has study found that Paxlovid (Nirmatrelvir-ritonavir) did not reduce the risk of developing long COVID for vaccinated, non-hospitalised individuals during their first COVID infection. The study also revealed a higher proportion of individuals with acute symptoms rebound and test-positivity than previously reported.

The study, by a team of researchers from UC San Francisco, is published in the Journal of Medical Virology.

Paxlovid treatment for acute COVID has been shown to be effective for high-risk unvaccinated individuals. But the effect of the treatment on long COVID risk, including whether it protects vaccinated people from getting long COVID, has been less clear.

The research team selected a group of vaccinated people from the UCSF Covid-19 Citizen Science study who had reported their first positive test for COVID-19 between March and August of 2022 and who were not hospitalised.

Some of these participants reported taking oral Paxlovid treatment during the acute phase of their COVID infection, while others did not.

In December of 2022, they were invited to answer a follow-up survey with questions about long COVID, COVID rebound symptoms and how long they continued to test positive.

Researchers found the two groups were similar. About 16% of those treated with Paxlovid had long COVID symptoms compared to 14% of those who were not treated with the medication.

Commonly reported symptoms included fatigue, shortness of breath, confusion, headache, and altered taste and smell.

Those who took Paxlovid and then went on to develop long COVID reported as many long COVID symptoms as those who were not treated with Paxlovid.

A small percentage of people developed severe long COVID, and those who had received Paxlovid were just as likely to have severe Long COVID symptoms as those who did not.

Among individuals who experienced symptomatic improvement during Paxlovid treatment, 21% reported rebound symptoms.

And among those with rebound symptoms, 10.8% reported one or more Long COVID symptom compared to 8.3% without rebound symptoms.

For participants who repeated antigen testing after testing negative and completing treatment, 25.7% reported rebound test positivity.

In total, 26.1% reported rebound symptoms or test positivity.

“We found a higher proportion with clinical rebound than previously reported but did not identify an effect of post-treatment rebound on long COVID symptoms,” said study first author Matthew Durstenfeld, MD, MAS, a cardiologist and UCSF assistant professor of Medicine.

“Our finding that Paxlovid treatment during acute infection is not associated with lower odds of long COVID surprised us, but it is consistent with two other rigorously conducted studies finding no difference in post-COVID conditions between 4 and 6 months after infection.”

The authors note that the study may have been impacted by limitations arising from its observational nature with researchers relying on patient self-reporting of treatment and Long COVID symptoms.

Source: University of California San Francisco Medical Center

Categories : COVID VaccinesTags :

Half Dose of COVID Booster Yields Similar Immune Response to Full One

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Reducing the dose of a widely used COVID booster vaccine produces a similar immune response in adults to a full-dose with fewer side effects, according to a new study published in The Lancet Regional Health – Western Pacific. The research found that a half dose of a Pfizer COVID booster vaccine elicited a non-inferior immune response to a full dose in Mongolian adults who previously had AstraZeneca or Sinopharm COVID shots. But it found half-dose boosting may be less effective in adults primed with the Sputnik V COVID vaccine. 

The research, led by Murdoch Children’s Research Institute (MCRI) and the National Centre for Communicable Diseases in Mongolia, is part of an international clinical trial investigating the different COVID booster shot approaches to help guide future vaccination strategies. 

The first batch of findings, and involving 601 participants over 18 years old from Mongolia, reports on the initial responses seen 28-days after vaccination. The study is the first of its kind to assess and compare COVID-19 vaccines widely used in low- and middle-income countries.

MCRI Professor Kim Mulholland, who also sits on the WHO SAGE committee, said the study found that fractional doses elicited an immune response that was non-inferior to a full dose with fewer side effects and was less costly.

“Fractional dosing may improve COVID booster acceptability and uptake and reduce the per-dose cost of COVID-19 booster programs,” he said. “Policymakers and immunisation advisory committees can draw upon this data to make flexible boosting schedules decisions.”

The study found that participants receiving a half dose reported fewer local reactions than those receiving full doses (60% versus 72%) including less pain and tenderness. They also reported fewer systemic reactions (25% vs 32%) including less fevers, vomiting, diarrhoea and headaches. 

The cohort will be followed up at six and 12 months with the data to answer key questions on other aspects of the immune response including the rate of waning and breakthrough infections. 

Source: Murdoch Children’s Hospital