News in brief: Antibiotic prescribing halved during pandemic; ‘Prolonged immune response’ observed with third COVID vaccine dose; Plastic particle exposure reflected in bloodstream

Wednesday, 27 Apr 2022

Antibiotic prescribing halved during pandemic

The number of antibiotics prescribed in Australia fell by as much as 50% during the COVID-19 pandemic, a study has shown.

An analysis of outpatient antibiotic prescriptions issued from January 2014 to April 2021 showed that the number of prescriptions dropped sharply as national restrictions were implemented at the start of the pandemic in March 2020 and remained lower than usual during the period studied.

In winter 2020, there were 1,432,000 prescriptions per month compared to 2,313,000 the same month in 2019, a 38% reduction. Summer 2021 showed a 23% reduction in prescriptions compared to the summers of 2018 , according to Dr Jack Skeggs of Monash Infectious Diseases, Monash Health.

The reductions were predominantly in antibiotics such as amoxicillin used to treat community-acquired respiratory infections which showed a 52% reduction in prescribing the winter of 2020 compared to pre-pandemic levels. Prescription of antibiotics such as trimethoprim commonly used for other indications, remained stable.

Some of the reduction is likely to be due to the social distancing measures introduced to curb COVID-19 also reducing the spread of other respiratory infections, Dr Skeggs suggested.

He said it was notable that reductions occurred in all states and territories despite significant differences in COVID-19 case numbers and duration of lockdowns

“This is particularly promising as it suggests that the reductions were not dependent on high case numbers or the most onerous social distancing measures like lockdowns and it may therefore be possible to maintain some of the decreases after the pandemic,” he said.

“Our finding that certain broad-spectrum antibiotics like amoxicillin-clavulanate appear to be being prescribed for community-acquired respiratory infections suggests that antibiotic prescribing for respiratory illness remains a valuable target for future anti-microbial stewardship programs,” he added.

The findings were presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Lisbon, Portugal.

‘Prolonged immune response’ observed with third COVID vaccine dose

Most of the approved COVID vaccines induce prolonged protection when administered as a third dose, highlighting the value of global booster programmes, according to the latest data from the UK’s COV-BOOST study.

The study, which is being led by University Hospital Southampton across 18 NIHR-supported sites, compared the immune response from seven vaccines 28 days after administration as a third dose in 2,883 participants who had received two initial doses of either the AstraZeneca or Pfizer vaccines.

The findings, published online in the Journal of Infection, showed that strong immune responses were still seen 84 days after third jabs with AstraZeneca, Pfizer, Moderna, Janssen and Novavax vaccines (only Pfizer, Moderna and AstraZeneca have been used in the UK booster programme).

In those who had two initial doses of AstraZeneca, third doses of the Pfizer and Moderna mRNA vaccines resulted in the highest level of anti-spike antibodies 84 days post administration, while in those who had had initial doses of Pfizer there was no significant difference between those given a third jab of AstraZeneca or Pfizer, the researchers noted. However, an even stronger anti-spike antibody response was seen in those given Janssen’s jab as a third dose after two doses of Pfizer.

Also of note, the researchers found that the rate that immune cell responses dropped off at a similar rate after third doses of all the vaccine combinations and doses.

Plastic particle exposure reflected in bloodstream

Micro- and nanoplastic particles from ingested or inhaled sources such as personal care products, dental polymers and nanomedicines have been detected in the human bloodstream.

A Dutch biomonitoring study used double shot pyrolysis-gas chromatography/ mass spectrometry (Py-GC/MS) to measure polymer mass concentrations in blood samples from 22 healthy volunteers.

The study found 77% of donors (n = 17) carried a quantifiable mass of plastic particles in their blood. Polyethylene terephthalate (PET) was the most widely encountered (in 50% of donors), followed by polymerised styrene (36%), polyethylene (23%) and poly(methyl methacrylate) in 5%.

“This indicates that at least some of the plastic particles humans come in contact with can be bioavailable and that the rate of elimination via e.g. the biliary tract, kidney or transfer to and deposition in organs is slower than the rate of absorption into the blood,” the study said.

The researchers said the duration of plastic particles in the bloodstream and the health effects are as yet unknown.

Read more in Environment International

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