Day: October 8, 2021

Differences in Natural and Vaccine-induced COVID Immunity Revealed

Source: Fusion Medical Animation on Unsplash

A new study recently published in Nature has found that immune protection resulting from COVID protection creates lasting effects in memory B cells.

Unlike circulating antibodies, which peak soon after vaccination or infection only to fade a few months later, memory B cells can remain to ward off severe disease for decades. They also evolve over time, learning to produce successively more potent ‘memory antibodies’ that are more effective at neutralising the virus and with better adaptation to variants.

Though vaccination instils higher levels of circulating antibodies than natural infection, the study suggests that not all memory B cells are created equal. While vaccination gives rise to memory B cells that evolve over a few weeks, natural infection births memory B cells that continue to evolve over several months, producing highly potent antibodies adept at eliminating even viral variants.

Though the findings suggest an advantage from natural infection over vaccination, this does not outweigh the dangers of illness and death from COVID, the researchers warn.

“While a natural infection may induce maturation of antibodies with broader activity than a vaccine does – a natural infection can also kill you,” explained Professor Michel C. Nussenzweig, head of Rockefeller’s Laboratory of Molecular Immunology. “A vaccine won’t do that and, in fact, protects against the risk of serious illness or death from infection.”

When any virus enters the body, immune cells immediately release circulating antibodies, which decay at variable rates depending on the vaccine or infection. They may confer protection for months or years but then dwindle in number, allowing possible reinfection.

Long term protection is provided by memory B cells that produce memory antibodies. Studies suggest that memory B cells for smallpox last at least 60 years after vaccination; those for Spanish flu, nearly a century. And while memory B cells don’t necessarily block reinfection, they can prevent severe disease.

Recent studies have suggested that within five months of receiving a vaccine or recovering from a natural infection, some no longer retain sufficient circulating antibodies to keep the novel coronavirus at bay, but memory B cells remain vigilant. Until now, however, scientists did not know whether the vaccines could be expected to provide the sort of robust memory B cell response seen after natural infection.

Prof Nussenzweig and colleagues resolved to tease out any differences in memory B cell evolution by comparing blood samples from convalescent COVID patients to those from never-infected mRNA-vaccinated individuals.

Vaccination and natural infection elicited similar numbers of memory B cells, which rapidly evolved between the first and second dose of the Pfizer and Moderna vaccines, producing increasingly potent memory antibodies. But after two months, progress stalled. The memory B cells were present in large numbers and expressed potent antibodies, but the antibodies were not getting any stronger. Also, although some of these antibodies were able to neutralize Delta and other variants, there was no overall improvement in breadth.

The researchers found that in convalescent patients, however, memory B cells continued to evolve and improve up to one year after infection. With every memory B cell update, more potent and more broadly neutralising memory antibodies were coming out.

There are several potential reasons that memory B cells produced by natural infection might be expected to outperform those produced by mRNA vaccines, the researchers said.

It is possible that the body responds differently to viruses that enter through the respiratory tract than those that are injected. Or perhaps an intact virus goads the immune system in a way the vaccines’ spike protein antigens simply cannot. It may also be possible that the virus persists in the naturally infected for weeks, giving the body more time to mount a robust response. The vaccine, on the other hand, is flushed out of the body mere days after triggering the desired immune response.

Memory B cells appear to undergo limited bouts of evolution in response to mRNA vaccines, a finding which may have significant implications for booster shots. A booster with the current mRNA vaccine would likely stimulate memory cells to produce antibodies strongly protective against the original virus and somewhat less so against the variants, Prof Nussenzweig said.

“When to administer the booster depends on the object of boosting,” he said. “If the goal is to prevent infection, then boosting will need to be done after 6 to 18 months depending on the immune status of the individual. If the goal is to prevent serious disease, boosting may not be necessary for years.”

Source: Rockefeller University

Older Patients with Advanced Lung Cancer Suffer Reduced Mobility

Source: Miika Luotio on Unsplash

New research found that older patients with non-small cell lung cancer often have low life-space mobility prior to starting lung cancer treatment. Life-space mobility is the ability to move within one’s environment from the home to the wider community. The findings were published in the Journal of the American Geriatrics Society.

The study recruited 93 patients aged 65 to 94 with advanced NSCLC starting palliative chemotherapy, immunotherapy, and/or targeted therapy from a Comprehensive Cancer Center, Veterans Affairs, and safety-net clinic. Patients completed geriatric assessments including Life-Space Assessment (LSA) pretreatment and at 1, 2, 4, and 6 months after treatment initiation. 

The Life-Space Assessment scores had a range of 0 to 120, with a score under 60 being considered restricted. The researchers found that the average pretreatment score was 67. On average, the score fell by 10 points from pretreatment to one month after treatment started and remained low at six months.  

The decline at one month was greater among patients with high anxiety. On the other hand, a lower body mass index prior to starting treatment was associated with an improvement in the score during treatment.  

“Life-space mobility is a well-studied patient-centered outcome in general aging research but is only now being examined for older adults with cancer,” said lead author Melisa L. Wong, MD, MAS, of the University of California, San Francisco. “Our study’s novel design provided a unique lens into how quantitative changes in life-space mobility are experienced qualitatively by older adults with lung cancer.”

Source: Wiley

Hypertension Drugs Linked to Psoriasis

Source: Unsplash

A review of studies has found an association with the use of antihypertensive medications and the development of psoriasis.

Psoriasis is a chronic inflammatory skin disease that, when inflicted, can be detrimental to the individual’s overall quality of life. The prevalence rate of psoriasis is 0.1–11%, more common in Caucasian and Scandinavian populations, and also more common in older people and in high-income countries as well.

In the analysis, which is published in the British Journal of Clinical Pharmacology, data from 13 studies indicated that angiotensin-converting-enzyme inhibitors, beta- blockers, calcium-channel blockers, and thiazide diuretics may increase the risk of psoriasis. However, there was no greater increase of any of the drugs relative to the others.

The authors of the analysis propose several mechanisms by which blood pressure medications may affect an individual’s risk of developing skin conditions.

“Our findings indicate that patients who take antihypertensive drugs should be carefully monitored for psoriasis,” said senior author Hye Sun Gwak, PharmD, PhD, of Ewha Womans University, in Seoul.

Source: Wiley

Digital COVID Vaccination Certificates for South Africa are Here

Photo by Priscilla Du Preez on Unsplash

People vaccinated in South Africa can now download their digital COVID vaccination certificates. The service officially went live on Friday, and was announced by the Minister of Health, Dr Joe Phaahla.

Addressing a media briefing, Dr Phaahla said the certificate could be used for travel and tourism, sport and recreation events, music festivals, shops that are providing discounts and prizes for people who are vaccinated.

“Our role is to make this tool available to the nation to provide people with the proof of vaccination so they can have access to the many amenities and activities that some have been missing…

“The vaccination certificate was introduced over the last three days while it was in the testing phase but some people have been able to upload it to their cell phones.

“We are launching the first phase of the certificate – there’s going to be a lot more improvements in the next two months [with regards to] the safety and security of the certificate but it is ready for use,” said the Minister.

The certificate was developed by the Department of Health and the Council for Scientific and Industrial Research (CSIR) and can be found at https://vaccine.certificate.health.gov.za.

The project manager for the National Electronic Vaccination Data System (EVDS), Milani Wolmarans, said the certificate can be downloaded through a web portal by anyone who has received the COVID vaccine in South Africa.

“You’ll need your vaccination code from the SMS you received after your vaccination, South African ID or Foreign Passport number or Asylum or Refugee number. This should be the same document that you presented when you got vaccinated and the cell phone you included on your registration,” she said.

Vaccination codes will be sent via SMS over the next four day, and also be accessed from the COVID call centre on 0800 029 999.

“With regards to the recognition of the digital certificate, most countries around the globe would accept the certificate. It is, however, dependent on the policy of the country that you would be visiting and also what their verification requirements would be.

“Towards the end of the next two months, there will be an app that you can use to download the certificate,” Wolmarans said.

The Minister also welcomed South Africa’s removal from the UK’s red list, which will take effect on Monday 11 October.

“We are also pleased with the UK government announcement that it is taking our country from the red list – meaning more easy travel between people from South Africa and the UK. The UK will be recognising the certificate that we are launching,” Dr Phaahla said.

Importantly, the UK will also now recognise South African COVID vaccination certificates.

Source: SA News.Gov

Minimal Risk Found for Home Birth With a Licensed Midwife

Photo by William-Fortunato on Pexels

Minimal Risk Found for Home Birth With a Licensed Midwife
In the US state of Washington, a planned home birth with a licensed midwife is just as safe as a birth at a licensed birth centre, according to researchers from the University of British Columbia and Bastyr University.

The research team of midwives, epidemiologists and obstetricians came to this conclusion after analysing outcomes of community births in Washington state between 2015 and 2020. The findings were reported in Obstetrics & Gynecology. A previous US study had shown that pregnancy outcomes with care provided by midwives had lower risks of caesarean and preterm birth than those with physician care.

The study analysed data from 10 609 home and birth centre births from midwives. Births met the professional association guidelines and were within regulatory standards. This included individuals with healthy pregnancies who were carrying to term with no history of caesarean delivery, and a foetus oriented for head-first birth.

“The birth setting had no association with increased risk for either parent or baby,” said lead author Elizabeth Nethery, PhD candidate at UBC. “Our findings show that when a state has systems to support the integration of community midwives into the healthcare system as Washington has done, birth centers and homes are both safe settings for birth.”

In the US, home birth is still controversial. The American College of Obstetricians and Gynecologists (ACOG) has stated that birth is safest at a hospital or an accredited birth centre, recommending against home birth because of countrywide studies that show higher rates of neonatal death among home births.

However, individual states have wide variations in licensing requirements, regulatory status and access to medications for midwives. These variations might contribute to differences in state level outcomes and reflected in national statistics.

Washington has worked to integrate midwifery into the healthcare system, with 3.5% of all births with midwives or at state-licensed birth centres. As a result, there is a low rate of 0.57 perinatal deaths per 1000 births, comparable to other countries where home birth is well-integrated into the health system and classed as low risk by ACOG.

“Washington provides a model for midwifery care and safe community birth that could be replicated throughout the U.S.,” said Nethery. “Currently, some U.S. states currently have no licensure available for community birth midwives at all, and this could be contributing to poorer birth outcomes in those states.”

Source: University of British Columbia

Insects Carry a Range of Antimicrobial-resistant Bacteria

A study published in Nature Microbiology has for the first time provided compelling evidence of connections between antimicrobial-resistant bacteria causing surgical-site infections and insects and other arthropods. Among these bacteria are those with resistance to drug-of-last-resort. 

Antimicrobial resistance (AMR) could render many of the current mainstay and last-resort antibiotics useless, resulting in many more deaths from previously treatable infections. A UN report estimated in 2019 that AMR could lead to ten million deaths per year, and cost the world $100 trillion, by 2050.

“Similar to our experience over the last eighteen months with the pandemic, a problem currently seen from afar will quickly come into focus much closer to home” said Professor Tim Walsh at Oxford University

The report found that:

  • About 20% of the flies, cockroaches, spiders, moths, and ants were carrying carbapenem resistance.
  • Of these, 70-80% were carrying extended spectrum cephalosporin resistance, that is, enzymes that confer resistance to most beta-lactam antibiotics, including penicillins, cephalosporins, and the monobactam aztreonam.
  • Currently there are about 18 million flies to every human, but conservative global warming projections estimate insect and fly population will double if temperatures increase by 1.5 degrees.
  • By 2080 there could be around 50 000 trillion flies carrying carbapenem resistance and spreading AMR across the planet.

“Similar to our experience over the last eighteen months with the pandemic, a problem currently seen from afar will quickly come into focus much closer to home,” said Prof Walsh. “The clinical burden of AMR is most felt in low-middle income countries, but the increase in global temperatures, due to climate change, will result in a significant increase in flies and many other insects and a subsequent increase in the global velocity of antibiotic resistance.” Prof. Tim Walsh, Oxford University.

AMR is a pervasive issue, stretching from hospitals to farming and human waste processing. Resistance can spread within hospitals, communities, farms, and wastewater systems, and domestic animals can share AMR microorganisms with humans.

One tactic is to repurpose previously developed drugs that did not work for humans and use these for animals, buying time for us to develop new drugs.

Another is to rethink hospital prevention and infection control measures, especially in lower- and middle-income countries. Further research into how arthropods disseminate AMR and improving healthcare infrastructure to reduce the spread of AMR by arthropods.

“Most antibiotics currently used on animals are also the same that are used in humans, creating a pool where bacteria can evolve to evade drugs and then reinfect humans,” said Prof Tim Walsh of Oxford University.

“There is no silver bullet when it comes to tackling the worldwide threat of AMR,” he added. “The Ineos Oxford Institute for AMR Research is committed to finding non-human antibiotic therapies and feeds for animals, addressing the increase in AMR in human infections and raising awareness of this hidden threat to human health. But this is a global medical crisis that ultimately will only be resolved with a global response.”

Source: Oxford University