COVID-19 Scan for Apr 06, 2022

News brief

Fourth COVID vaccine dose boosts protection against infection, severity

A study in Israel during the Omicron variant surge finds that rates of COVID-19 infection and severe illness were lower after a fourth dose of the Pfizer/BioNTech vaccine than after three doses, and while protection against infection waned quickly after 4 weeks, protection against severe disease was still strong at 6 weeks.

The study, published yesterday in the New England Journal of Medicine (NEJM), involved data from 1,252,331 people aged 60 years and older, who became eligible for a fourth COVID-19 shot in Israel on Jan 2, 2022. The study period ran from Jan 10 to Feb 18 for severe illness and to Mar 2 for infection.

The unadjusted rate of COVID-19 infections per 100,000 person-days among people who had received a fourth vaccine dose 8 days before was 1.5, compared with 3.9 in those who had received three doses and 4.2 in controls who had received a fourth dose 3 to 7 days before.

After adjustment, the rate of severe COVID-19 in the fourth week after receipt of the fourth vaccine dose was lower than that of the three-dose group by a factor of 3.5 (95% confidence interval [CI], 2.7 to 4.6) and lower than that in controls by a factor of 2.3 (95% CI, 1.7 to 3.3).

Vaccine protection against severe infection was stable for 6 weeks after the fourth dose. The unadjusted rate of severe COVID-19 infection per 100,000 person-days was 177 in fourth-dose recipients, 361 in the three-dose group, and 388 in controls.

The adjusted rate of infection among those who had received a fourth dose 4 weeks earlier was lower than that in the three-dose group by a factor of 2.0 (95% CI, 1.9 to 2.1) and lower than that of controls by a factor of 1.8 (95% CI, 1.7 to 1.9).

"These analyses provided evidence for the effectiveness of a fourth vaccine dose against severe illness caused by the omicron variant, as compared with a third dose administered more than 4 months earlier," the researchers wrote. "For confirmed infection, a fourth dose appeared to provide only short-term protection and a modest absolute benefit."
Apr 5 NEJM study

C-sections, inductions dropped during first months of COVID-19

Fewer in-person prenatal visits during the first months of the COVID-19 pandemic resulted in a 6.5% drop in premature caesarian sections (C-sections) and inductions, according to a new study in Pediatrics. The research was conducted by a team at Georgia Tech's School of Economics.

This is the first major study to examine pandemic-era birth data at scale, the authors say, and it raises questions about how and if some medical interventions may unnecessarily result in preterm deliveries.

The study was based on 39 million US births from 2010 through 2020. Using data from the National Center for Health Statistics, researchers forecasted expected premature births—babies born before 37 weeks of pregnancy—from March to December of 2020, and compared these to actual outcomes seen during those months.

From March 2020 to December 2020, the number of preterm births from C-sections or induced deliveries remained 0.35 percentage points below the predicted values, which meant 350 fewer preterm C-sections and induced deliveries per 100,000 live births, or 10,000 fewer overall during the study period, the authors said.

"While much more research needs to be done, including understanding how these changes affected fetal deaths and how doctors triaged patient care by risk category during the pandemic, these are significant findings that should spark discussion in the medical community," Daniel Dench, PhD, lead of author of the study, said in a Georgia Tech press release.
Apr 6 Pediatrics study
Apr 6 Georgia Tech press release

News Scan for Apr 06, 2022

News brief

Study: Dogs, cats share resistant bacteria, resistance genes with owners

Observational research set to be presented later this month at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) suggests close contact with pets could result in sharing of multidrug-resistant bacteria and resistance genes.

For the study, researchers from the University of Lisbon in Portugal and the Royal Veterinary College collected fecal samples from healthy companion animals (CAs, specifically dogs and cats) and their owners from 41 households in Portugal and 42 households in the United Kingdom at monthly intervals for 4 months.

They screened fecal samples for carbapenem-resistant Enterobacterales or Acinetobacter spp. and for extended-spectrum beta-lactamase (ESBL) or plasmid-mediated AMPc (pAMPc) genes.

No carbapenem-resistant Enterobacterales or Acinetobacter were found, but 15 of 103 CAs (14.6%) and 15 of 112 humans (13.2%) harbored ESBL/pAMPc-producing Enterobacterales (ESBL-E). Of these, 7 CAs (6 in Portugal and one in the United Kingdom) and 5 household members (4 in Portugal and 1 in the United Kingdom) carried at least one multidrug-resistant strain.

In four Portuguese households, the ESBL/pAMPc resistance genes found in pets matched those in their owner's stool samples. In three of these households, matched resistance genes were only recovered at one time point, but in one household, sharing of strains was noted at two consecutive timepoints, suggesting a persistent colonization of shared bacteria within the household.

In addition, in two of the households, the microbes in pets matched Escherichia coli strains in their owner's stool sample, but in the other two, there was no evidence of bacteria sharing.

"Although the level of sharing from the households we have studied is low, healthy carriers can shed bacteria into their environment for months, and they can be a source of infection for other more vulnerable people and animals such as the elderly and pregnant women," study coauthor Juliana Menezes, PhD, of the University of Lisbon, said in an ECCMID press release.

"Our findings reinforce the need for people to practice good hygiene around their pets and to reduce the use of unnecessary antibiotics in companion animals and people."
Apr 5 ECCMID abstract
Apr 5 ECCMID press release

H5N6 avian flu hospitalizes man in China

China has reported another H5N6 avian flu infection, with an illness reported in a 28-year-old man from Henan province in the central part of the country.

In a statement, Hong Kong's Centre for Health Protection (CHP) said investigators found the man had contact with poultry before he got sick. His symptoms began on Mar 18, and he was hospitalized the next day, where he is listed in critical condition.

The man's illness marks China's 11th H5N6 case of the year. So far, it has reported 75 cases since the virus was first detected in humans in 2014.

H5N6 circulates in poultry in a few Asian countries, but only China and Laos have reported human cases. The infections are most common in adults who have contact with poultry and are often severe or fatal.
Apr 6 CHP statement