News Scan for Aug 25, 2020

Asymptomatic COVID-19 spread
Sex-specific COVID immune response
Heart attacks and flu
Africa free of wild poliovirus
Yellow fever in Senegal

COVID-19 spread noted in 'healthy' concertgoers 2 days after infection

Seemingly healthy people with COVID-19 can spread the disease to others as soon as 2 days after infection, an analysis of a coronavirus cluster traced to four live music clubs in Osaka, Japan, shows.

The study, published today in the Journal of Infectious Diseases, extracted data on club-goers linked to an 108-person cluster from the Japanese Ministry of Health, Labour and Welfare website. The first case in the cluster was identified on Feb 27, and the outbreak was contained by Mar 17.

Of the 51 asymptomatic people infected with SARS-CoV-2, the virus that causes COVID-19, who visited one music club only once, 10 remained asymptomatic at coronavirus diagnosis after, on average, 20 days. The 41 club-goers with symptoms became ill 2 to 17 days after exposure.

Three people who attended concerts who remained asymptomatic at diagnosis spread the coronavirus to as many as three family members or coworkers each.

The authors said that the results underscore the continued need for crowd avoidance and good personal hygiene amid the pandemic. Activities such as talking, singing and shouting have been shown to generate virus-containing aerosols that hang in the air for hours. "Seemingly healthy people could spread SARS-CoV-2 during intense activities in enclosed environments without sufficient ventilation," they wrote.
Aug 25 J Infect Dis study


Study identifies sex differences in levels of antibodies against COVID-19

Concentrations of antibodies against SARS-CoV-2 began to decline 4 to 5 weeks after diagnosis in 159 patients who recovered from COVID-19, with men showing a significantly stronger immune response than women—which could account for the poorer outcomes seen in men, according to a Swiss study published yesterday in the Journal of Infection.

Researchers analyzed participants' antibody concentrations for 8 weeks, starting 2 weeks after a positive coronavirus test result. After a median of 5 weeks after diagnosis, 4.6% to 6.5% of participants had not developed measurable levels of one of three types of coronavirus antibodies, which the investigators said may be due to a missing or delayed immune response to COVID-19. "We speculate this to be secondary to a suspected virus' ability to modify or suppress innate immune responses," they wrote.

The decline in two different types of immunoglobulin G (IgG) antibodies from weeks 8 to 10 was significant, which the authors said contrasts sharply with the 34-week or longer IgG immune response to SARS-CoV-1, the virus that causes severe acute respiratory syndrome (SARS).

Compared with women, men had substantially higher levels of all antibodies, but especially of immunoglobulin A (IgA). The authors said that the sex-specific differences may be due to ongoing infection in men.

The early drop in antibody concentrations should affect the interpretation of serological results obtained at specific time points, especially for disease surveillance, they said.

"After SARS-CoV-2 infection, the immune system seems to produce different amounts of IgG and IgA in women and men, possibly helping to explain the higher risk of adverse COVID outcome in men through a stronger (inflammatory) response," the researchers wrote. "If confirmed on other cohorts, these observations should be considered when assessing the efficacy and safety of novel vaccine candidates against SARS-CoV-2."
Aug 24 J Infect research letter


12% of adults hospitalized for flu have acute heart problems, study finds

A study today in the Annals of Internal Medicine shows that acute cardiovascular events, including heart failure and ischemic heart disease, occur in almost 12% of  adult patients hospitalized for influenza.

The study was based on more than 80,000 US patients whose outcomes were tracked via the US Influenza Hospitalization Surveillance Network during the 2010-11 through 2017-18 flu seasons.

Older age, tobacco use, underlying cardiovascular disease, diabetes, and renal disease were significantly associated with higher risk of cardiovascular events, the authors said. Among the 11.7% of patients with cardiovascular events, acute heart failure (6.2%) and acute ischemic heart disease (5.7%) were the most common. Adults vaccinated against flu were significantly less likely to suffer a cardiac event.

According to the authors, "Acute cardiovascular events are important contributors to influenza-related morbidity and mortality. Almost one third of patients with an acute cardiovascular event were admitted to the intensive care unit, and 7% (6% excluding those with cardiogenic shock) ultimately died during hospitalization."

In an accompanying commentary, Chandini Raina MacIntyre, PhD, said the study offers strong evidence for assessing all adult flu patients for cardiovascular health and vaccination status.

"Influenza may unmask undiagnosed cardiovascular disease and may exacerbate known disease," MacIntyre writes. "Cardiovascular disease is the leading cause of morbidity and mortality globally, so by preventing a proportion of acute cardiovascular events, influenza vaccination will have a substantial public health benefit and will likely be cost-beneficial."

The study is the latest in a string of research detailing the risk of heart attacks with flu, including a 2018 study that showed the risk of a heart attack increasing sixfold in the first 7 days of flu.
Aug 25 Ann Intern Med study
Aug 25 Ann Intern Med commentary
Jan 25, 2018, CIDRAP News story "Study bolsters link between flu and heart attack"


African region declared free of wild poliovirus

After a decades-long effort to document polio cases, immunization, and surveillance in 47 countries, an independent certification board today declared that the World Health Organization's (WHO's) African region is free of wild poliovirus (WPV). In a statement, the WHO said the last WPV case was reported from Nigeria in 2016 and that the achievement marks the second virus eradication in the region, alongside smallpox.

African governments formally committed to eradicate the disease, which was paralyzing an estimated 75,000 children each year, in 1996. That same year, Nelson Mandela, with support from Rotary International, launched the Kick Polio Out of Africa campaign. The WHO credits polio eradication efforts with preventing 1.8 million children from being paralyzed and preventing about 180,000 deaths.

Matshidiso Moeti, MBBS, who directs the WHO's African regional office, said in a statement, "This is a momentous milestone for Africa. Now future generations of African children can live free of wild polio."

The Global Polio Eradication Initiative (GPEI) today in a statement congratulated African governments on the achievement and said five of the WHO's six regions—making up 90% of the world's population—are now free of WPV, moving the world closer to polio eradication. However, it noted that continued commitment is needed to boost immunization and health systems in order to battle circulating vaccine-derived poliovirus type 2, which is present in 16 African countries.
Aug 25 WHO African regional office statement
Aug 25 GPEI statement


Yellow fever infects Senegal child

Senegal has reported its first yellow fever case since early 2018, which involves a 5-year-old girl from an area with low vaccine coverage, the WHO's African regional office said in its weekly outbreaks and health emergencies report today.

The girl's symptoms began on Jun 24, and she was initially seen and treated by a traditional healer. She is from the Darou Marnane Ndia area of Touba, Senegal's second-largest city, which is located in the central part of the country.

When her illness persisted, she was treated at a health center, where a blood sample was obtained and tested as part of arbovirus syndromic surveillance at the Pasteur Institute in Dakar. Testing was delayed owing to the demands of the COVID-19 response.

The investigation found that the girl wasn't up to date on her immunizations. Active case searching didn't identify any other cases, and 10 children from the patient's home were vaccinated.

A larval survey of water sources near the patient home found mosquito infestation rates above 22%, and a high proportion were Aedes aegypti, a known carrier of the yellow fever virus. The WHO noted that the detection is Senegal's first since February 2018. WHO officials praised the action of Touba authorities, noting that continued follow-up is needed.
Aug 25 WHO African regional office weekly report

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