Invivyd, a biotechnology company based in Massachusetts, today announced that it has submitted a request with the US Food and Drug Administration (FDA) for an emergency use authorization (EUA) for its monoclonal antibody to prevent COVID-19.

The drug, called VYD222, is a broadly neutralizing, half-life extended monoclonal antibody for pre-exposure use in immunocompromised adults and adolescents. In a statement, the company said the EUA filing is supported by a phase 3 trial and ongoing in vitro studies to assess its activity against SARS-CoV-2 variants such as JN.1. The clinical trials have been testing a 4,500-milligram dose given by intravenous infusion.

No approved monoclonal antibodies

Currently, there are no monoclonal antibodies authorized or approved by the FDA. In January 2023, the FDA pulled its EUA for an earlier monoclonal antibody preventive called Evusheld after data suggested that it was unlikely to be active against certain SARS-CoV-2 variants.

Dave Hering, MBA, Invivyd's chief executive officer, said, "We believe that the demonstrated durability of VYD222 is reflective of our strategy to select antibody candidates that target conserved epitopes to achieve our stated goal of keeping pace with viral evolution." He added that many immunocompromised people don't achieve full benefit from COVID-19 vaccines, and pre-exposure treatments can provide an important new prevention option.

If the drug is authorized, the company hopes to make VYD222 rapidly available soon afterward.

Yesterday in the Journal of Infectious Diseases, researchers described a 2016 mpox outbreak that affected 20 captive chimpanzees at a sanctuary in central Cameroon.

At the time of the clade 1 outbreak in August through October, the sanctuary housed about 300 chimpanzees, gorillas, and monkeys in 18 groups. Mpox affected 20 of 23 adult and younger chimpanzees (14 male and 9 female) in one group. No animals had been moved into or out of the group in the previous 6 months.

Better monitoring, control measures needed

From August to September, 3 chimpanzees were confirmed to have mpox, and 17 had probable cases, for an 87% attack rate. The most common signs were rash (90%), lethargy (85%), and facial or peri-laryngeal swelling (70%). Two of the animals died, for a case-fatality rate of 10%. The rest of the chimpanzees recovered and were considered no longer infectious by late October.

Control measures should include quarantining affected animals, limiting human contacts, surveillance of humans and animals, use of personal protective equipment, and regular decontamination of enclosures.

After the first mpox case was detected, the sanctuary reported it to the Cameroon Epidemiological Network for Animal Diseases, and the onsite veterinarian documented daily signs, dates of onset and death, movements between cages, and treatment in the affected group. Nose-throat and rectal swabs were collected from chimpanzees who died or were immobilized for treatment.

For the 17 unaffected groups, caretakers visually inspected each animal each day for mpox signs, behavioral changes, and night shelter use, and a veterinarian did the same at least twice a week. Animals were quarantined if they showed mpox signs or had direct or indirect contact with the affected group.

Animal caretakers were monitored daily for mpox signs for 17 days; none developed a characteristic rash or fever.

"There is a need for increased awareness and a One Health approach to preparation for outbreaks in wildlife rescue centers in primate range states were MPXV [mpox virus] occurs," the researchers wrote. "Control measures should include quarantining affected animals, limiting human contacts, surveillance of humans and animals, use of personal protective equipment, and regular decontamination of enclosures."

Hong Kong researchers estimate that 33.6% of the adult population had COVID-19 in 2022, 72.1% with no symptoms, according to an analysis published yesterday in Emerging Infectious Diseases.

Chinese University of Hong Kong investigators examined the seroprevalence of open reading frame 8 (ORF8) antigens against SARS-CoV-2 to estimate the number of people infected during a spike in Omicron BA.2 variant cases from March to June 2022. In late February 2022, the government mandated self-reporting of positive rapid antigen testing (RAT).

A total of 1,028 volunteers who reported no history of COVID-19 infection gave plasma samples for enzyme-linked immunosorbent assay (ELISA) with ORF8 protein as an antigen. The researchers estimated infections using a model based on rates of positive ELISAs relative to the number of patient-reported cases from the Hong Kong Department of Health.

The median participant age was 50 years, 63.9% were women, and all but one reported receiving more than two doses of COVID-19 vaccines.

'Not surprising' Omicron wave was uncontrollable

Of all participants, 2.5% had evidence of a previous COVID-19 infection. Among the total population, 16.2% were reported to have had COVID-19 by RAT (6.1%) or reverse transcription polymerase chain reaction (RT-PCR; 10.1%).

Public health agencies need to take into account the potential for substantial undercount of actual numbers of infections when considering the commitment of resources to prevent and control outbreaks.

Using estimates from their statistical model, the authors inferred that 33.6% (95% credible interval, 32.1% to 34.8%) of the 7.5 million Hong Kong residents (roughly 2.5 million) contracted COVID-19 from January to June 2022. They estimated that 41.8% of reported infections and 72.1% of total cases were asymptomatic.

"With such a large number of unrecognized cases circulating the virus in the community, it was not surprising that the Omicron outbreak was uncontrollable, even though stringent measures, such as contact tracing and quarantine for close contacts, continued to be in effect," the authors wrote. "Public health agencies need to take into account the potential for substantial undercount of actual numbers of infections when considering the commitment of resources to prevent and control outbreaks."