Health

First Covid-19 reinfection documented in Hong Kong, researchers say – STAT

Published

4 years ago

August 24, 2020

Researchers in Hong Kong on Monday reported what appears to be the first confirmed case of Covid-19 reinfection, a 33-year-old man who was first infected by SARS-CoV-2 in late March and then, four and a half months later, seemingly contracted the virus again while traveling in Europe.

The case raises questions about the durability of immune protection from the coronavirus. But it was also met with caution by other scientists, who questioned the extent to which the case pointed to broader concerns about reinfection.

There have been scattered reports of cases of Covid-19 reinfection. Those reports, though, have been based on anecdotal evidence and largely attributed to flaws in testing.

But in this case, researchers at the University of Hong Kong sequenced the virus from the patient’s two infections and found that they did not match, indicating the second infection was not tied to the first. There was a difference of 24 nucleotides — the “letters” that make up the virus’ RNA — between the two infections.

“This is the world’s first documentation of a patient who recovered from Covid-19 but got another episode of Covid-19 afterwards,” the researchers said in a statement.

Experts cautioned that this patient’s case could be an outlier among the tens of millions of cases around the world and that immune protection may generally last longer than just a few months. They said that ongoing studies tracking patients who had recovered from Covid-19 would help reach more definitive conclusions. They also noted that the man’s second case was milder than his first, indicating that his immune system was providing some level of protection, even if it could not prevent the infection entirely.

“There’s been more than 24 million cases reported to date,” Maria Van Kerkhove, a coronavirus expert at the World Health Organization, said at a briefing Monday, when asked about the Hong Kong report. “And we need to look at something like this at a population level.”

The question of how long someone is protected from Covid-19 after being infected and recovering looms large.

Studies are increasingly finding that most people who recover from the illness mount a robust immune response involving both antibodies (molecules that can block the virus from infecting cells again) and T cells (which can help clear the virus). This has suggested that people would be protected from another case for some amount of time.

But based on what happens with other coronaviruses, experts knew that immunity to SARS-CoV-2 would not last forever. People generally become susceptible again to the coronaviruses that cause the common cold after a year or even less, while protection against SARS-1 and MERS appears to last for a few years.

“What we are learning about infection is that people do develop an immune response, and what is not completely clear yet is how strong that immune response is and for how long that immune response lasts,” Van Kerkhove said. She added she was still reviewing the Hong Kong case.

The strength and durability of the immune response is also a crucial factor in how long vaccines will be effective for, and for how often people might need a booster dose.

In the Hong Kong case, the man had traveled to Spain and returned to Hong Kong via the United Kingdom. A saliva sample was taken upon arrival in Hong Kong as part of a screening protocol and tested positive for SARS-CoV-2 on Aug. 15.

During his second infection, the man did not have any symptoms. Some patients go through their course of Covid-19 without showing symptoms, but researchers have also hypothesized that secondary cases of the coronavirus will generally be milder than the first. Even if immune systems can’t stop the virus from infecting cells, they might still rally some level of response that keeps us from getting sicker. During his first case, the patient had classic Covid-19 symptoms of cough, fever, sore throat, and headache.

Experts said it was also important to consider the immune response the patient generated after his first infection. While most people seem to mount a solid response, there has been indication that some people do not produce neutralizing antibodies — those that can block the virus from infecting cells — at very high levels, for unclear reasons.

“The fact that somebody may get reinfected is not surprising,” said Malik Peiris, a virologist at the University of Hong Kong, who is not an author of the paper describing the reinfection but is familiar with the case. “But the reinfection didn’t cause disease, so that’s the first point. And the second thing is that it is important to know whether the patient mounted a neutralizing antibody response to the first infection or not. Because the vast majority of patients in our experience do mount a good neutralizing antibody response. So is this person an outlier or is he likely to be the average person infected?”

Even if the Hong Kong case is an outlier, it points to a few implications: For one, people who have recovered from Covid-19 should also be vaccinated, the researchers said. And they should continue following precautions like wearing a mask and physical distancing.

Helen Branswell contributed reporting.

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Health

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

Published

18 hours ago

September 13, 2024

Anne Joseph

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.

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

Published

2 days ago

September 11, 2024

Anne Joseph

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

Published

3 days ago

September 10, 2024

Anne Joseph

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.

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