COVID Booster: Mucus miracles, kids’ antibodies and good news on side effects but bad news on death toll.

Mucus is the hero saving us from surface-touching infections

The more we’ve learned about COVID, the less likely we’ve thought it is that you can catch it from touching an infected surface. A paper in ACS Central Science has proposed a reason for this: proteins from human mucus, called mucins, seem to be pretty good at blocking coronaviruses when dry.

Mucins have sugars attached to them. The researchers, who are based at the University of Utah, US, found that coronaviruses bind to these sugars when there aren’t human cells around, meaning the sugars form a barrier preventing coronavirus particles from getting into people.

After testing on a non-COVID coronavirus and lab-based mammal cells, the researchers found that a drop of mucus allowed to dry on a surface for even a few minutes was sufficient time to lower the risk of infection.

“This research explains how the mucins work, which we think is important,” says senior author, Assistant Professor Jessica Kramer.

“If we understand how they block the virus from infection, we can develop drugs that mimic that action.”

If they happen, 92% of mRNA vaccine side effects aren’t serious

A meta-analysis in The Lancet Infectious Diseases has reported that, of the 298 million mRNA vaccines administered in the US over the first six months of the rollout, 92% of the 340,522 reported side effects weren’t serious.

The analysis relies on data from the Vaccine Adverse Event Reporting System, and a smartphone survey system called the v-safe system.

The most common adverse effects were (wait for it) injection site pain, fatigue, fever, and headache. These effects were listed as more common after the second dose.

Around 15% of the 22,000 listed serious side effects were shortness of breath. The database is also required to report all deaths following vaccination, regardless of cause, and 1.3% of these serious side effects were death. The researchers say that the deaths are consistent with the rate of death in the general population.

“The rapid pace at which COVID-19 vaccines were administered under emergency use, especially among older populations, was unprecedented. Due to their age, this group already has a higher baseline mortality rate than the general population and our results follow similar patterns of death rates for people in this age group, following other adult vaccinations,” says study author Dr David Shay, a researcher at the US Centers for Disease Control.

Kids might be less likely to develop antibodies once catching COVID-19

Kids who have recovered from COVID-19 might be less likely to develop antibodies than adults, according to a study from the Murdoch Children’s Research Institute and the University of Melbourne.

The study, which is published in JAMA Network Open, examined blood samples from 57 children and 51 adults who’d tested positive to SARS-CoV-2.

Despite having similar viral load, children had lower “seroconversion”: the process of developing antibodies following an infection.

The researchers conclude that this means children may be more vulnerable to COVID-19 reinfection.

Third dose really is needed against Omicron

A study in The BMJ has found that two doses of a vaccine works against the Alpha and Delta variants, but you need a third dose of an mRNA vaccine to properly lower your risk of being hospitalised with the Omicron variant.

The researchers examined 11,690 hospital records from 21 US hospitals between March 2021 and January 2022 – 5728 COVID-19 cases, and 5962 COVID-free controls. The time of year was used to judge the most likely variant that patients were infected with.

While two doses of an mRNA vaccine provided 85% protection against hospitalisation during both the Alpha and Delta periods, they were only 65% effective in the Omicron period. Three doses brought this up to 86%.

Unvaccinated adults got sickest during the Delta period, followed by Alpha and then Omicron.

COVID-19’s death toll could be over three times the official amount

The official COVID-19 death toll from the start of 2020 to the end of 2021 was 5.9 million. But a new study in The Lancet suggests that this could be a vast underestimate, finding the true number to be more like 18.2 million.

The study tracks excess deaths (death rates that are higher than would normally be expected) around the world from between 1 January, 2020, and 31 December, 2021. It is the first study to do this on a global scale.

The total estimate of excess deaths from this paper is 18.2 million. COVID deaths appear to be particularly under-reported in sub-Saharan Africa and South Asia. Australia, Iceland, Singapore, New Zealand, and Taiwan all recorded negative excess mortality in this period – fewer people died than would be expected.

“Understanding the true death toll from the pandemic is vital for effective public health decision-making,” says lead author Dr Haidong Wang, of the Institute for Health Metrics and Evaluation, US.

“Studies from several countries, including Sweden and the Netherlands, suggest COVID-19 was the direct cause of most excess deaths, but we currently don’t have enough evidence for most locations. Further research will help to reveal how many deaths were caused directly by COVID-19, and how many occurred as an indirect result of the pandemic.”