COVID-19 roundup: 4th dose protective, risk of blood clots
COVID-19 roundup: 4th dose protective, risk of blood clots

COVID-19 roundup: 4th dose protective, risk of blood clots

In this week’s roundup, the latest scientific research on coronavirus, including its treatments and vaccines, suggests that a fourth dose of the Pfizer-BioNTech vaccine is extremely protective, patients with COVID-19 have a higher risk of blood clots in the eye and mental problems increase the risk for breakthrough infections.

Fourth vaccine dose protects vs omicron for at least one month

A fourth dose of the Pvizer-BioNTech COVID-19 vaccine provided significant additional protection against serious illness, hospitalization, and death for at least one month in the elderly, according to a study conducted in Israel when the omicron variant was dominant.

The estimated efficacy of the fourth dose during days 7 to 30 after it was administered compared to a third dose given at least four months earlier was 45% for infection, 55% for symptomatic disease, 68% for hospitalization, 62% for serious illness and 74% for death, the research team reported on Wednesday in New England Journal of Medicine. The study compared 182,122 people aged 60 years and older who received a fourth dose and 182,122 very similar individuals who had received a third dose but not a fourth.

“The results of our actual study suggest that a fourth dose of vaccine is effective at least initially against the omicron variant,” the researchers said. “Further follow-up will allow for further assessment of the protection that the fourth dose provides over time,” they added. A recently published major Israeli study who only looked at the number of breakthrough infections and serious illness after the fourth dose, found that the effect diminished rapidly in relation to infection but remained stable in relation to serious illness.

COVID-19 may increase the risk of rare eye clots

Patients with COVID-19 may have an increased risk of rare vision-threatening blood clots in the eye for several months afterwards, new findings suggest.

Because SARS-CoV-2 infections increase the risk of blood vessel obstruction elsewhere in the body, researchers examined nearly half a million COVID-19 patients to see if they would develop blood clots in the veins or arteries of the retina, the nerve tissue at the back of the eye , which receives images and sends them to the brain. Over the next six months, 65 patients had a retinal vein occlusion. Although that number is low, it reflects a statistically significant increase of 54% compared to pre-COVID-19 infection rates, according to a report published Thursday in JAMA Ophthalmology. Retinal artery clots were 35% more common after COVID-19 than before, but this difference may be due to chance. Blood clots most often occurred in patients with other conditions that increased their risk of blood vessel problems, such as diabetes, high blood pressure and high cholesterol.

The risk of blood clots did not appear to be associated with the severity of the coronavirus infection. The study could not prove that COVID-19 caused the blood clots in the eyes of these patients, the researchers noted, saying that larger studies of the problem are needed.

Risk of breakthrough infections associated with psychiatric problems

People with mental health problems have a higher risk of breakthrough infections after receiving COVID-19 vaccines, new data show.

Researchers in California tracked more than a quarter of a million fully vaccinated patients in the U.S. Veterans Affairs health system. Almost all were men, and about half had received at least one psychiatric diagnosis within the past five years. Overall, 14.8% developed COVID-19 infections despite vaccination. Compared with study participants without a psychiatric diagnosis, those over the age of 65 with substance abuse, psychotic disorders, bipolar disorder, adjustment disorder or anxiety had a 24% higher risk of breakthrough infections, the study found. For those under 65, risks were up to 11% higher than for those without a psychiatric history, the researchers reported Thursday at the JAMA Network Open.

“Our research suggests that increased breakthrough infections in people with psychiatric disorders may not be entirely explained by sociodemographic factors or pre-existing conditions,” said study leader Aoife O’Donovan of the San Francisco VA Health Care System. “It is possible that immunity after vaccination decreases faster or stronger for people with psychiatric disorders, and / or they may have less protection against newer variants,” she added.

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