News Scan for Nov 11, 2021

COVID and nursing home staff
COVID-19 vaccines and cancer patients
Trial of multi-strain Ebola vaccine
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Tests reveal much higher COVID rate in unvaccinated nursing home staff

Positive COVID-19 test results were more than 10 times more common among unvaccinated, asymptomatic healthcare professionals (HCP) in Veterans Health Administration (VHA) long-term care facilities than among their fully vaccinated counterparts, according to a research letter yesterday in JAMA Network Open.

Researchers at the VA Boston Healthcare System tracked mandatory weekly COVID-19 test results among 1,269 HCP and twice-weekly antigen testing among 704 more from Jan 15 to Jun 8, 2021.

Each month, lower rates of COVID-19 infection were identified in vaccinated versus unvaccinated asymptomatic HCP. Of 52,557 tests of 1,973 HCP, 25 (1.3%) tested positive for COVID-19 (0.3% vaccinated, 3.6% unvaccinated). Contact tracing linked one HCP infection with an asymptomatic, fully vaccinated resident.

By the end of the study period, 70.3% of HCP and 90% of residents were fully vaccinated. Infection rates began to decline in both groups along with a drop in community transmission.

"The yield of positive test results was much higher in HCP who were unvaccinated than those who were vaccinated, consistent with an evolving literature that suggests full vaccination status reduces asymptomatic SARS-CoV-2 infection in HCP," the study authors wrote.

"The observation that surveillance was primarily beneficial in HCP who were unvaccinated during periods of high community transmission is consistent with recent guidance from the Centers for Disease Control and Prevention and presents a quandary regarding how to identify and differentially test HCP who are unvaccinated in the absence of mandatory vaccination policy," they added.

The researchers noted that the proportion of false-positive COVID-19 tests will increase as infection rates fall, even among unvaccinated HCP, which will sometimes lead to unnecessary quarantine of essential HCP.

"Hence, the utility of frequent surveillance will vary as a function of the rate and trend of community transmission, vaccination status of HCP and residents, and the transmissibility of variant strains of SARS-CoV-2," they said.
Nov 10 JAMA Netw Open research letter


Study shows cancer patients can safely receive COVID-19 vaccines

A study yesterday in the Journal of Clinical Oncology shows COVID-19 vaccines are safe in people undergoing treatment for cancer and produce modestly impaired immune responses. Booster vaccine doses, however, enhance immunity.

The study was based on 762 active oncology patients at Massachusetts General Hospital, who were compared to 1,638 healthy controls. The patients were currently receiving cancer treatments, including chemotherapy, bone marrow transplants, corticosteroids, and radiation. All three vaccines currently used in the United States were included in the study.

The mRNA vaccines elicited a stronger immune response in cancer patients than the Johnson & Johnson adenovirus-based vaccine. But regardless of vaccine type, antibody titers and neutralization were quantitatively lower in cancer patients, the authors said. Prior COVID-19 infection (7.1% of the cohort) was associated with higher immune responses, and older patient age was associated with a diminished vaccine response.

Thirty-two cancer patients included in the study also had received a third booster dose of vaccine. In 30 of 32 study subjects, researchers recorded increased antibody titers (geometric mean concentration, 1.05 before the additional dose, 3.17 after). The Centers for Disease Control and Prevention now recommends all immunocompromised vaccine recipients, including cancer patients, receive a booster dose.

"Our data suggest that patients with cancer should receive mRNA vaccines," said co-lead investigator Justin Gainor, MD, director of the Center for Thoracic Cancers at Massachusetts General Hospital, in a press release. "In addition, patients who received the J&J [Johnson & Johnson] vaccine should be considered for additional vaccine doses."

Side effects were no worse in study subjects compared to controls.
Nov 10 J Clin Oncol study


Multivalent Ebola vaccine enters clinical trial

Oxford University today announced the launch of a multivalent (multi-strain) Ebola virus vaccine, which targets the two species likely to infect humans.

The small phase 1 trial is enrolling 26 healthy UK adults ages 18 to 55 with the goal of assessing immune response and safety, the university said in a statement. The vaccine targets the Zaire and Sudan strains and uses the same adenovirus vector as the AstraZeneca-Oxford COVID-19 vaccine.

Participants will receive one dose and be monitored over the next 6 months. Researchers expect results in the second quarter of 2022. Another phase of the trial is expected to launch in Tanzania by the end of 2021.

Daniel Jenkin, MBChB, MSc, principal investigator, said Ebola can be caused by different species, and each may require a targeted immune response to offer protection. He added that nearly all Ebola cases and deaths have been caused by the two species contained in the vaccine.

Also, Paola Cicconi, MD, the trial's chief investigator, said there's an unmet need for a multivalent vaccine, and experience with the AstraZeneca-Oxford COVID-19 vaccine shows that a product using the same adenovirus vector can be rapidly scaled up at a low cost and can be kept in storage conditions suited to developing countries.
Nov 11 Oxford University statement

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