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XBB.1.5 updated COVID vaccine booster offers 54% increased protection against symptomatic infection – News-Medical.Net

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In a recent study published in Morbidity and Mortality Weekly Report, researchers estimated the effectiveness of the 2023-24 updated coronavirus disease 2019 (COVID-19) vaccine.

The Advisory Committee on the Immunization Practices of the United States (US) Centers for Disease Control and Prevention (CDC) recommended on September 12, 2023, that all individuals aged six months or older receive the 2023-24 updated monovalent COVID-19 vaccine. The updated vaccine contains a component from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB.1.5 lineage and lacks ancestral strain components.

The JN.1 lineage was identified in the US in September 2023, which harbors 30 additional mutations in the spike (S) protein compared to XBB.1.5. Real-time reverse-transcription polymerase chain reaction (RT-PCR) results can help distinguish some SARS-CoV-2 lineages. S-gene target failure (SGTF) is detected in JN.1 and other BA.2.86 lineages, whereas S-gene target presence (SGTP) is detected in most lineages from 2023, including XBB.

Study: Early Estimates of Updated 2023–2024 (Monovalent XBB.1.5) COVID-19 Vaccine Effectiveness Against Symptomatic SARS-CoV-2 Infection Attributable to Co-Circulating Omicron Variants Among Immunocompetent Adults — Increasing Community Access to Testing Program, United States, September 2023–January 2024. Image Credit: New Africa / Shutterstock

About the study

In the present study, researchers estimated the effectiveness of the 2023-24 updated COVID-19 vaccine against symptomatic infection. They included tests conducted between September 21, 2023, and January 14, 2024, among adults reporting at least one symptom. Cases were individuals with a positive nucleic acid amplification test (NAAT).

Controls were individuals with a negative NAAT. The team excluded tests from Janssen vaccine recipients, Novavax recipients, immunocompromised individuals, those who received the most recent vaccine dose within a week preceding testing, and those with a positive COVID-19 test within the past 90 days.

Vaccine effectiveness (VE) against symptomatic COVID-19 was estimated by comparing the odds of receipt of the updated vaccine versus non-receipt among cases and controls. Multivariable logistic regression was used to estimate odds ratios. VE was computed separately by SGTP and SGTF status. Test-positive samples with reduced or null S-gene amplification were deemed to have an SGTF, whereas those without SGTF were considered SGTP.

Findings

Of over 9,200 NAAT results for individuals with symptoms of COVID-19-like illness, 3,295 tested SARS-CoV-2-positive. Around 1,125 individuals received the updated COVID-19 vaccine ≥ seven days earlier. More controls received the updated vaccine than cases. The median time from the last dose among updated vaccine recipients was 60 days for cases and 51 days for controls.

Nearly 8,100 individuals did not receive the updated vaccine. Of these, 30% were non-vaccinated and 70% were vaccinated. Among the vaccinated, the median time since vaccination was 378 days for cases and 363 days for controls. The estimated VE was 57% in the 18–49 age group and 46% among those aged ≥ 50. VE was estimated at 58% and 49% among people tested 7–59 and 60–119 days after receiving the updated vaccine, respectively.

There were 679 tests available with S-gene target results. Of these, 258 showed SGTF, and 421 exhibited SGTP. VE was not precise for tests with SGTF during the 7–59 days post-receipt of the updated vaccine, given the emergence of JN.1 in the US. VE during the 60–119 days post-receipt of the updated vaccine was 60% for tests with SGTP and 49% for those with SGTF.

Conclusions

The study provided early efficacy estimates of the updated monovalent XBB.1.5 vaccine against symptomatic infection and the first VE estimates against the JN.1 lineage. These VE estimates include data up to 119 days post-vaccination. However, VE will likely wane with time since vaccination, as observed after the original monovalent or bivalent COVID-19 vaccination. Prior infection history, medical conditions, and vaccination status were self-reported, thereby subject to recall bias.

Besides, the VE estimates were computed for a population that opted to be tested for COVID-19; therefore, the estimates are subject to selection biases. Further, coverage of the updated vaccine is low among adults and varies by age. Taken together, the updated monovalent vaccine provided 54% protection from symptomatic illness. Waning of the VE is expected over time, especially against less severe outcomes.

Journal reference:
  • Link-Gelles R, Ciesla AA, Mak J, et al. Early Estimates of Updated 2023–2024 (Monovalent XBB.1.5) COVID-19 Vaccine Effectiveness Against Symptomatic SARS-CoV-2 Infection Attributable to Co-Circulating Omicron Variants Among Immunocompetent Adults — Increasing Community Access to Testing Program, United States, September 2023–January 2024. MMWR Morb Mortal Wkly Rep, 2024, DOI: 10.15585/mmwr.mm7304a2, https://www.cdc.gov/mmwr/volumes/73/wr/mm7304a2.htm

 

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Canada to donate up to 200,000 vaccine doses to combat mpox outbreaks in Africa

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The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.

It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.

Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”

Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.

Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.

A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.

On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.

Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”

But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”

“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.

Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.

Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.

Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.

“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.

“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”

This report by The Canadian Press was first published Sept. 13, 2024.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

The Canadian Press. All rights reserved.

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How many Nova Scotians are on the doctor wait-list? Number hit 160,000 in June

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HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.

The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.

Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.

“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”

The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.

A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.

Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.

“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.

Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.

The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.

“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.

This report by The Canadian Press was first published Sept. 11, 2024.

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Newfoundland and Labrador monitoring rise in whooping cough cases: medical officer

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ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.

Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.

Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.

Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.

The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.

“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.

Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.

Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.

Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.

A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.

This report by The Canadian Press was first published Sept. 10, 2024.

The Canadian Press. All rights reserved.

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