Study: First COVID-19 case likely occurred in November 2019
A modeling study yesterday suggests that the first human case of COVID-19 likely occurred in or November of 2019 in China, with the most likely date of origin being Nov 17. The study was published in PLOS Pathogens.
Using methods from conservation science, which is used to determine when species went extinct, scientists worked backward using the dates of the earliest known cases in 203 countries to determine when COVID-19 most likely originated. The method is called Optimal Linear Estimation (OLE) and can be used with sparse data sets, the authors said.
They concluded the likely origin date in China and also suggested the virus would have arrived in Japan on Jan 3, 2020, Spain on Jan 12, the United States on Jan 16, and Australia on Jan 23.
The date for the United States is 2 weeks prior to the earliest known American case, and almost 6 weeks before the first recognized case on Feb 26, the authors said.
“While the first case of COVID-19 was officially identified in early December, 2019, it is likely that SARS-CoV-2 had spilled over into humans much earlier,” the authors wrote. “In the same way the extinction events are rarely observed, so too are origination events such as those of COVID-19.”
In a PLOS press release, the authors said the conservation methods could be useful to epidemiologists studying future pandemics, as it “offers a new opportunity to understand the emergence and spread of diseases as it only requires a small amount of data.”
Jun 24 PLOS Pathog study
Jun 24 PLOS press release
ACIP approves dengue vaccine for endemic areas, tweaks flu vaccine advice
The vaccine advisory group to the Centers for Disease Control and Prevention (CDC) yesterday unanimously voted to recommend Sanofi’s dengue vaccine (Dengvaxia) for children ages 9 to 16 years who live in areas such as Puerto Rico where the disease is endemic.
The vaccine is given in three doses and requires a test to confirm that a child has had a previous dengue infection. Vaccination in someone who has never been exposed to dengue before can lead to a more severe future infection through a phenomenon called antibody-dependent enhancement.
An Advisory Committee on Immunization Practices (ACIP) working group has been studying the issue and drafted the recommendation, which the whole group discussed and voted on yesterday, according to Stat. The experts acknowledged that the rollout of the vaccine would be challenging, owin to lab testing before vaccination. Also, members discussed challenges regarding provider access to tests to assess previous exposure to dengue and to ensure that kids receive all three doses. However, the group was swayed by the benefits and manageable risks.
The Food and Drug Administration (FDA) approved Dengvaxia in May 2019 for children ages 9 to 16 who have had at least one lab-confirmed dengue infection.
In separate discussions, ACIP fine-tuned its flu vaccine recommendations, according to American Academy of Pediatrics (AAP) News. The committee green-lighted co-administration with COVID-19 vaccines and added guidance about flu vaccine timing for certain groups—such as for children ideally by the end of October. Also, ACIP said nonpregnant adults should avoid immunization in July and August because of concerns over waning immunity, and women in their third trimester should be vaccinated as soon as the vaccine is available to protect their babies.
On another topic, the group said children receiving pre-exposure rabies vaccination can receive two rather than three doses, similar to a change recommended earlier this year for adults.
Jun 24 Stat story
Jun 24 AAP News story
Backyard poultry Salmonella outbreak grows to 474 cases, 1 death
A US Salmonella outbreak linked to backyard poultry has grown by 311 cases, to 474 illnesses, and the CDC has reported the first outbreak death, according to a CDC update yesterday.
Three more states are affected (46 total) and a new serotype has been added (Salmonella Mbandaka) since the CDC’s first notice of the outbreak on May 20, and 41% of isolates have shown some degree of antibiotic resistance, the agency noted. Of 334 people with information available, 103 (31%) have been hospitalized, up from 34 on May 20. An Indiana patient has died.
Illness-onset dates range from Dec 15, 2020, to Jun 4, 2021, and 58% of case-patients are female. Patient ages range from less than 1 to 97 years, with a median age of 31, and 139 patients (30%) are children younger than 5 years.
Of 271 people interviewed, 209 (77%) reported contact with backyard poultry before getting sick.
“Epidemiologic and laboratory data show that contact with backyard poultry is making people sick,” the CDC says. “The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses.”
The agency recommends no close contact, such as snuggling, with backyard poultry, and to buy the animals from hatcheries that take steps to reduce Salmonella. Those who raise backyard birds should always wash their hands with soap and water immediately after touching poultry, their eggs, or their surroundings.
Jun 24 CDC update
Jun 24 CDC investigation details
May 21 CIDRAP News scan on initial outbreak notice
Third monkeypox case identified in UK index patient’s household
Officials confirmed a third monkeypox case in North Wales, England, according to the North Wales Chronicle yesterday. Both the new case and the second case involve people in the same household as the index patient, who had imported the disease when he or she traveled from Nigeria and followed COVID-19 quarantining procedures.
The story said that while the index patient has already made a full recovery, is not an infection risk, and has been discharged, the other two patients are still in the hospital. Public Health Wales and Public Health England are both monitoring the cases, and all close contacts have been identified.
Richard Firth, MPH, consultant in health protection at Public Health Wales, told North Wales Chronicle, “Confirmed cases of Monkeypox are a rare event in the UK, and the risk to the general public is very low.”
Monkeypox is endemic in central and West African countries, and it usually presents with mild symptoms and resolves on its own with no long-term effects.
Jun 24 North Wales Chronicle report
Jun 11 CIDRAP News scan on first cases
Four countries report more vaccine-derived polio cases
Four countries—Tajikistan in central Asia and three in Africa—reported more polio cases over the past week, all involving circulating vaccine-derived poliovirus type 2 (cVDPV2), the Global Polio Eradication Initiative (GPEI) said in its latest update.
Tajikistan reported nine new cases, all in Khatlon province in the southwest near the borders with Afghanistan and Uzbekistan. The latest infections push its total for the year to 15.
In Africa, Ivory Coast reported 1 more cVDPV2 case, which involves a patient from Bafing, which is counted in the 2020 total—now at 61. Nigeria reported 3 more cases, 1 in Yobe and 2 in Jigawa, lifting its 2021 total to 11. Also, South Sudan reported 2 more cases, in Unity and Upper Nile states, bringing its total for the year to 8.
Jun 24 GPEI weekly update