COVID Booster

Kids might (slightly) increase your chance of catching COVID-19

According to UK scientists, living with kids during the second wave of the pandemic increased the risk of catching COVID-19 – but didn’t increase the risk of death.

This is in contrast to the first wave, when no increase in COVID-19 was seen in parents – likely because schools were open during the second wave, the researchers say, allowing kids to pick up the virus and bring it home.

The research, published in the journal BMJ, looked at electronic health records from 12 million adults living with and without children during the first (Feb to Aug 2020) and second wave (Sep to Dec 2020) of the pandemic. After taking into account other factors associated with COVID-19 like age, sex, ethnicity, weight and health conditions, the study found that living with children was associated with an increased risk of recorded COVID-19 infection and COVID-19 related hospital admission.

However, the increased risk was only small. Between the first and second wave, the number of people with COVID-19 rose from 810 to between 850-870 per 10,000 people living with children aged 0-11 years, and to between 970-1,000 for those living with children aged 12-18 years.

COVID mortality dropped in wealthier countries

Mathematical analysis has revealed that wealthier areas of the United States and Europe experienced significantly lower death rates during the second wave of COVID-19. 

Most wealthy countries in Europe have drastically reduced their mortality rate during their second wave (with the exception of Germany and Sweden, whose rates decreased, but less only by a factor of 4) – the Netherlands saw a 16-fold decrease. The only country that saw an increased mortality rate was Belarus. The north-eastern states of the US, including New York, New Jersey and Connecticut, saw decreases in line with western European countries.

Europe covid second wave map1
Map of Europe showing change in COVID-19 mortality by country between first and second waves of infection.

The research team, led by the University of Sydney in Australia and Tsinghua University in Beijing, say that their results could have several different explanations. Perhaps the first-wave mortality rates were undercounted; or first-wave infections tended to disproportionately affect the elderly while second-wave infections tended to affect younger people. In general, countries with more equitable health systems saw lower mortality rates.

“Our work shows sharp drops in mortality with respect to reported cases and deaths,” says Max Menzie, co-author from Tsinghua University. “However, the problem will always be what is the true number of cases in the early first wave? We may never know, but we imagine future research and analysis will try to determine it.”

The research is published in the journal Chaos.

Slow walkers four times more likely to die from COVID-19

Walking speed may be an indicator of your risk of contracting COVID-19, according to UK researchers.

A study of over 400,000 middle-aged UK participants (with a median age of 68) found that slow walkers are more than twice as likely to catch a severe version of COVID-19 and nearly four times as likely to die from contracting it.

The research, led by the University of Leicester and publishedin the International Journal of Obesity, set out to determine whether simple measures of physical fitness could be important risk markers for COVID-19. The team examined the relative association of body mass index (BMI) and self-reported walking-pace with COVID-19 risks.

“Fast walkers have been shown to generally have good cardiovascular and heart health, making them more resilient to external stressors, including viral infection but this hypothesis has not yet been established for infectious disease,” lead researcher Tom Yates says.

“We know already that obesity and frailty are key risk factors for COVID-19 outcomes. This is the first study to show that slow walkers have a much higher risk of contracting severe COVID-19 outcomes, irrespective of their weight.”


In good news, this increase in infection didn’t translate to an increased risk of mortality. In fact, the researchers found that people living with children were less likely to die of any cause overall – and people living with children 0-11 were less likely to die from COVID-19 during both waves.

UK variant potentially more deadly

A study published in Naturehas found that the COVID-19 UK variant (B.1.1.7) is linked to a 55% increased risk of death compared to other new variants.

The researchers, led by the London School of Hygiene and Tropical Medicine in the UK, analysed data from more than two million community test results and over 17,000 COVID-19 deaths in England from September 2020 to February 2021. From this, they identified nearly 5,000 deaths of people who were confirmed to be infected with the variant, which was first detected in September 2020.

They found that the risk of death was 55% higher than for people infected with other variants, even after adjusting for factors like age, sex and ethnicity.

“This corresponds to the absolute risk of death for a 55–69-year-old male increasing from 0.6% to 0.9% within 28 days after a positive test in the community,” the researchers explain in their paper.

“Our analysis suggests that B.1.1.7 is not only more transmissible than pre-existing SARS-CoV-2 variants, but may also cause more severe illness.”

US cases might be double the number reported

A US study suggests that the number of COVID-19 cases in the USA may actually be double the number reported to the Centers for Disease Control and Prevention (CDC).

In a study published in JAMA Network Open, researchers looked for COVID-19 antibodies in a sample of 61,910 healthy people who didn’t think they had caught the virus. 

But the findings revealed that 4,094 of these people had COVID-19 antibodies.

Extrapolating this to the whole population, the researchers estimate that 16 million people may have had asymptomatic or undiagnosed infections as of September 30, 2020.

“Our estimate implied more than twice the number of infections than cases reported to Centers for Disease Control and Prevention, suggesting a more widespread pandemic,” the researchers write in their paper.

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