Kids with COVID-19 often have no symptoms; Smoking linked to vaccine response

GMA News – Published August 12, 2021 4:48am

After taking age into account, the only risk factors for lower antibody levels were male sex and smoking – and the gender difference might be because smoking rates were twice as high in men as in women, the researchers speculate.

Here is a summary of some recent studies on COVID-19. They include research that warrants further study to corroborate the findings and that have yet to be certified by peer review.

Asymptomatic COVID-19 very common

Roughly one-third of people with COVID-19 have no symptoms, according to a review of data from more than 350 studies published through April 2021.

Asymptomatic infections were more common in children than in the elderly or in people without preexisting medical conditions, said Pratha Sah of Yale School of Public Health, who led the analysis published on Tuesday in PNAS.

Her team estimates that 46.7% of infected children have no symptoms, she said.

“This is especially concerning because settings with close, extensive contact among large groups of younger individuals are particularly susceptible to superspreader events of COVID-19, which may go undetected” if school authorities only watch for symptoms.

Senior author Alison Galvani, also of the Yale School of Public Health, noted that asymptomatic individuals can still pass the virus to others, which makes mask wearing important as schools reopen.

Smoking may impair mRNA vaccine response

Current smokers may be at risk for lower immune responses to some COVID-19 vaccines, Japanese researchers say, though more research is needed before firm conclusions can be drawn.

In a preliminary study of 378 healthcare workers, ages 32 to 54, the researchers analyzed levels of protective antibodies induced by the mRNA vaccine from Pfizer and BioNTech, using blood samples obtained roughly three months after the second dose.

As has been found in previous studies, older participants had lower antibody levels.

After taking age into account, the only risk factors for lower antibody levels were male sex and smoking – and the gender difference might be because smoking rates were twice as high in men as in women, the researchers speculate.

In a paper posted on Saturday on medRxiv ahead of peer review, they report that antibody levels were higher in former smokers than in current smokers, which “suggests smoking cessation will reduce the risk of a lower antibody titer.” — Reuters

SOURCE: https://www.gmanetwork.com/news/scitech/science/799008/kids-with-covid-19-often-have-no-symptoms-smoking-linked-to-vaccine-response/story/