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Omicron: mRNA booster vaccine offers best protection – Medical News Today

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New research suggests a booster dose of an mRNA COVID-19 vaccine can protect well against the Omicron variant. Sven Hoppe/picture alliance via Getty Images
  • A recent study shows that two doses of mRNA (Pfizer-BioNTech or Moderna) and one dose of viral vector (Johnson & Johnson) COVID-19 vaccines were insufficient to produce adequate immunity to a lab-created Omicron variant or pseudovirus.
  • The Omicron pseudovirus infected cells at a higher rate than other pseudovirus variants.
  • The results demonstrated a booster dose of an mRNA COVID-19 vaccine provided the best immune protection from the Omicron pseudovirus.

Since its first detection in South Africa and Botswana in November 2021, the SARS-CoV-2 variant Omicron (B.1.1.529) has spread rapidly globally. Currently, Omicron is the leading variant of concern in the United States, accounting for about 98% of COVID-19 cases in the week ending January 8, 2022.

All viruses, including SARS-CoV-2, constantly change or mutate to form new variants. Mutations of the virus may result in the decline of the variant, while others cause the virus to thrive.

Dr. William Schaffner, professor of infectious diseases at the Vanderbilt University Medical Center in Nashville, provided some background in an MNT interview.

He explained: “When [SARS-CoV-2 viruses] mutate, they can, on occasion, […] create a variant virus that has new characteristics, you might call it a new personality, and the Omicron […] is one of those. Its surface protein compositions are similar to previous variants but a little bit different.”

Dr. Schaffner added: “So when that happens, the vaccines […] designed against the original [SARS-CoV-2] strains produce antibodies that […] [partially match] the surface structure of the Omicron variant. As a consequence, the protection is not as complete.”

There are currently three COVID-19 vaccines available in the U.S. The primary series consists of two doses of an mRNA vaccine (Pfizer-BioNTech or Moderna vaccines) or one dose of a viral vector vaccine (Johnson & Johnson).

The immune response to COVID-19 vaccines may wane over time and as new variants evolve. Boosters can help combat diminishing neutralizing antibody responses, but it is unknown how well current vaccines protect against Omicron.

This led researchers at the Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology, and Harvard to conduct a study to investigate the effectiveness of the primary series of COVID-19 vaccines and a booster dose of an mRNA vaccine.

They study’s results appear in the journal Cell. The researchers used a laboratory test validated in previous studies called a pseudovirus neutralization assay.

The scientists created harmless versions or pseudoviruses of the original strain (wild-type), Delta, and Omicron SARS-CoV-2 viruses. The researchers then used the assay to test blood samples from 239 vaccinated participants (111 with Pfizer-BioNTech, 88 with Moderna, and 40 with Johnson & Johnson).

The study included people residing in Chelsea, MA — an area with a high rate of COVID-19 — and employees of the Massachusetts General Brigham healthcare system. Participants ranged from 18–78 years old, and 63% were female.

The study stratified participants into five groups:

  • people who received the primary vaccination series in the past 3 months and never developed COVID-19 —recently vaccinated
  • people who received the primary vaccination series in the past 6–12 months and never developed COVID-19 —distantly vaccinated
  • people who received the primary vaccination series in the past 6–12 months and developed COVID-19 — distantly vaccinated with infection
  • people who received a booster dose of the Pfizer or Moderna vaccine in the past 3 months and never developed COVID-19 — booster

The researchers measured the neutralizing antibody response of the blood samples from the four participant groups against the wild-type, Delta, and Omicron pseudoviruses. Researchers found a decreased neutralizing antibody response to the Delta and Omicron pseudovirus versus the original variant.

With the Delta pseudovirus, neutralization was slightly reduced in the recently vaccinated, distantly vaccinated with infection, and booster groups, but undetectable in the distantly vaccinated group.

However, only the participants receiving the booster vaccination demonstrated robust Omicron pseudovirus neutralization, while the other groups showed substantial decreases in neutralization capability.

When researchers compared blood samples from the group recently receiving the primary series of the COVID-19 vaccines to those receiving a booster vaccine within the last 3 months, they found that those receiving boosters had a greater scope and cross-reactivity of neutralizing antibody response to the Omicron pseudovirus.

The researchers then tested the pseudoviruses’ ability to infect cells with and without the ACE2 receptors. ACE2 receptors are necessary for cell entry of SARS-CoV-2 in the body.

As expected, none of the pseudoviruses infected cells without ACE2 receptors. In cells with ACE2 receptors, the Omicron pseudovirus infected cells at a four times higher rate than the wild-type and twice the rate of Delta.

When asked to comment on the results of the study, Dr. Schaffner expressed that the lack of assessment of the role of cell-mediated immunity was a potential limitation, “but certainly [the study offered] a […] very clear explanation on the antibody side of the immune system.”

He elaborated:

“This is an elegant study that […] [develops] some laboratory evidence that helps us explain the behavior of the virus in the real world. It reinforces the notion […] that two doses of the mRNA vaccines, although they elicit good antibody levels, are not very effective in neutralizing the Omicron virus.”

Dr. Schaffner continued: “However, if you get a booster in addition to your two doses, […] you get more antibody, and you get more diverse antibodies with that booster, [which] turned out to be really quite effective, particularly [with] Omicron. They discovered […] that Omicron pseudovirus infected cells in the laboratory much more efficiently […] than did the pseudoviruses with the other variants — [which] helps explain the increased transmissibility of Omicron.”

In a White House press briefing regarding the Omicron variant on January 5, 2022, Dr. Rochelle P. Walensky, director of the Centers for Disease Control and Prevention (CDC), outlines the organisation’s current recommendations.

She states: “Vaccines and boosters are protecting people from the severe and tragic outcomes that can occur from COVID-19 infection. We’re asking everyone to follow these four steps: Get vaccinated and get boosted, if you are eligible, wear a mask, stay home when you’re sick, and take a test if you have symptoms or looking for greater extra reassurance before you gather with others.”

Dr. Schaeffner added, “The take-home point is clear — get vaccinated [with] the booster when you become eligible immediately. That will provide the best protection.”

For live updates on the latest developments regarding the novel coronavirus and COVID-19, click here.

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Nova Scotia reports 68 people in hospital because of COVID-19 – CBC.ca

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Nova Scotia has reported that 68 people are in hospital because of COVID-19, including 10 in intensive care.

A news release from the province Sunday said the patients are receiving specialized care in a COVID-19 designated unit.

The average age of the patients admitted for COVID-19 is 65, the release states. The majority of the patients, 65, were admitted during the Omicron wave. 

There are also two other groups currently in hospital related to the virus, according to the release.

  • 60 people who were identified as positive upon arrival but were admitted for another medical reason, or were admitted for COVID-19 but no longer require specialized care
  • 112 people who contracted COVID-19 after being admitted to hospital.

The abbreviated release did not provide the number of COVID-19 admissions and discharges. 

Nova Scotia Health labs completed 3,711 tests on Saturday and 696 new cases have been reported.

There are 447 cases in the central health zone, 108 in the eastern zone, 105 in the western zone and 36 in the northern zone.

Less than than 10 per cent of Nova Scotians are unvaccinated, according to provincial statistics.

As of Friday’s update, unvaccinated Nova Scotians were about four times more likely to be hospitalized due to COVID-19 than someone with two doses of vaccine. That is based on average hospitalizations since the province started releasing the daily hospitalizations by vaccine status on Jan. 4.

Summary offence tickets

Halifax Regional Police issued 11 summary offence tickets Sunday for violations of health regulations.

Police responded to reports of a party at a Bayers Road residence shortly before 1 a.m. Sunday.

Tickets were issued to 11 occupants for failing to comply with provisions of the Health Protection Act. 

The tickets carry a fine of $2,422.

Atlantic Canada case numbers

  • Newfoundland and Labrador reported one death and 384 new cases Sunday. There are 5,503 active cases and 12 hospitalizations. 
  • Prince Edward Island reported five hospitalizations Saturday. There were 309 new cases and 222 recoveries in Saturday’s report.
  • New Brunswick reported four more deaths and 115 hospitalizations Sunday. The province has 5,265 active cases.
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UK’s Johnson plans to scrap COVID-19 self-isolation law – The Telegraph

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The United Kingdom is drawing up plans under which people will not be legally bound to self-isolate after catching COVID-19, The Telegraph reported on Sunday.

Prime Minister Boris Johnson wants to permanently revoke emergency coronavirus laws as Britain’s COVID-19 cases continue to fall, the report said, adding official guidance would remain but would not result in fines or legal punishment if ignored.

The plans will be worked up over the coming weeks, with an announcement expected as early as the spring, the report said.

Last week, Health Secretary Sajid Javid said COVID-19 self-isolation in England will be cut to five days from seven if someone tests negative twice.

Johnson is also set to lift Plan B COVID-19 restrictions, introduced last month to slow the spread of the Omicron variant, according to an earlier Telegraph report.

 

(Reporting by Maria Ponnezhath in Bengaluru; Editing by Daniel Wallis)

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'Choose increased antibodies over brand': Moderna appointments still being cancelled in London, Ont. area – CTV News London

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Doctors and pharmacists continue to advocate for people to get the first available mRNA vaccine for their COVID-19 booster dose.

“We have had some feedback that appointments are being canceled because people are holding out for Pfizer,” says Dr. Joyce Lock, the medical officer of health for Southwestern Public Health (SWPH).

“I strongly strongly urge everyone, particularly those over the age of 50, to choose increased antibodies over brand,” she added.

Lock made those statements during her weekly briefing on Jan 12.

“Our immunity following our original two doses is decreasing over time,” says Lock. “Our bodies don’t care what brand they receive. They follow the science, not the manufacturer. Studies show that immunity shoots back up after the booster and it doesn’t matter which brand.”

This week, First Ave. Pharmacy in St. Thomas, Ont. took to Facebook saying it had openings due to people refusing Moderna as a booster dose.“We send out a mass email saying that there’s a shortage of Pfizer and we might have to offer them Moderna and some people would cancel their appointment online or they would call us and cancel their appointments,” says Minh Nguyen, pharmacist at First Ave. Pharmacy. “Both Moderna and Pfizer are mRNA vaccines and equally effective at preventing severe illness from COVID. So I would say get whatever mRNA vaccine you can.”

Sunday, the Metrolinx Go-VAXX bus returned to London, Ont. It was stationed in the parking lot at the new East Lions Community Centre on Brydges St.

They had some appointments booked, but we were even taking walk-ins with Pfizer being administered.

“I’ve had Pfizer for my first two shots and that’s what I preferred,” says Michael Sean MacVoy, a truck driver getting his booster. “At this point, I didn’t care.”

Diane Crozman was in the same scenario, getting Pfizer a third time. “It doesn’t really make a difference to me,” she said. “They said the Moderna is going to work the same, but Pfizer that’s good because I’ve already got the other two Pfizer.”

Justin Seaward showed up for a walk-in booster, minutes after his wife went home from her booked appointment.

“I’ve had Pfizer, Moderna, then Pfizer now,” says Seaward. “It didn’t really make a difference much to me. I just wanted to be Vaxxed so I can feel safer for my family.”The Middlesex-London Paramedic Service (MLPS) had administered 2,194 doses of vaccine over the past six days since starting pop-up clinics in Middlesex County.

The percentage of people upset that Moderna was being administered is very low.

“It has happened a few times at the front door, but very rare,” says Miranda Bothwell, acting superintendent for special operations with MLPS.

They will be back on the road, continuing their pop-up clinic tour Monday in Lucan, Ont. 

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