August Updates: The Covid-19 Research You Might Want to Hear

Dear readers,

Here’s a brief look into the 13 articles (friend linked) in Microbial Instincts last month in chronological order. Note that some of these will be added to the publication later. And articles #10, 11, and 12 are related to strains of SARS-CoV-2.

1. “Why Masks Protect Its Wearer Too: The Virus Load Concept:” Researchers took an overlooked view about face masks. We often hear that face masks prevent one from spreading the disease. But it also limits one from inhaling too many virus particles. A lower viral load would make it easier for the immune system to overcome. And many lines of direct animal and indirect human evidence support this proposition.
2. “How Antibiotics Could Alter the Child’s Mind and Body Development:” The health risks of antibiotics for children undergoing critical development phase are discussed. Studies have shown that early-life antibiotic exposure (within 1–2 years old) is an independent risk factor for future weight gain and poor neurodevelopmental outcomes. And this risk is greater for broad-spectrum antibiotics, which is still given carelessly today.
3. “Covid-19 Was a Ticking Time-Bomb, Scientists Warned Since 2007:” The coronavirus research has sped up since the 2003 SARS epidemic. Researchers then realized the vast diversity of coronaviruses circulating in bats that are capable of infecting human cells and cause diseases in mice. Even direct spillover of bat coronavirus to humans had happened in rural areas. Therefore, Covid-19 may just be a matter of time. And this warning has been neglected since 2007.
4. “Another Reason the US Is Struggling More With Coronavirus than Some Nations Abroad: BCG Vaccination:” Bo Stapler, MD, discussed a study describing the striking country-level correlation between BCG vaccination (for tuberculosis; TB) and Covid-19 death rates. He further discussed what the BCG vaccine means for this pandemic; for instance, “How does the TB vaccine protect against the novel coronavirus?” or “Should we all go out and get the BCG vaccine?”
5. “Prior Common Cold: A Protective Factor Against Covid-19?:” Studies found that people never faced SARS-CoV-2 somehow had immune T-cells that reacted to SARS-CoV-2 proteins. And a new study has confirmed that cross-immunity exists where T-cells can outsmart the novel coronavirus by learning from prior common cold-causing coronaviruses. This gives the immune system a headstart, so it does not mount non-specific immune responses (e.g., anti-fungal, anti-parasitic, etc.) against SARS-CoV-2.
6. “Recovered Covid-19 Cases Still Show Brain Anomalies 3 Months Later:” A study found persistent neurological symptoms and structural brain alterations in Covid-19 patients at 3-month post-hospital discharge, even in mild cases. However, the human brain displays a remarkable capacity to self-renew. Indeed, the study also found evidence suggesting brain regeneration at play in those recovered Covid-19 patients.
7. “The Latest Theory That May Answer the Origin of Covid-19:” The Mojiang Miners Passage (MMP) hypothesis could explain many oddities of the pandemic, such as its ability to infect the lower respiratory tract, unusual adaptability to humans within a short timeframe, and mysterious zoonotic transfer from bats in Yunnan to people in Wuhan. This hypothesis also does not contradict known facts that SARS-CoV-2 came from bats — not pangolin, human-designed, or the Huanan wet market in Wuhan.
8. “Coronavirus Found in Wastewaters: What Does it Mean for the Pandemic:” The persistent fecal shedding of infectious SARS-CoV-2 has led wastewater contamination. But waterborne transmission of SARS-CoV-2 is unlikely as SARS-CoV-2 is an enveloped virus that can easily be deactivated during wastewater sanitization procedures. Nonetheless, there is value in wastewater-based epidemiology that has helped disease surveillance and prevented Covid-19 outbreaks.
9. “Is it Flu or Covid-19? Fever or Cough First Could Tell the Difference:” A new study calculates the most likely sequence of events (i.e., order of clinical symptoms) for Covid-19, SARS, MERS, and influenza from available datasets. Results showed that fever is usually the first presenting symptom for coronavirus infections and cough for flu.
10. “Why A Milder Variant of Coronavirus (Δ382) Just Disappeared:” Scientists discovered a ∆382 variant of SARS-CoV-2 with reduced virulence compared to the original virus. The ∆382 variant has a 382-nucleotide deletion in gene regions that code for the ORF8 protein, which helps SARS-CoV-2 to avoid being killed by T-cells. But the ∆382 variant has gone extinct, which might be due to the strict pandemic control measures or weakened virulence yet no boost in transmissibility.
11. “Many Strains of Coronavirus Are Out There, but Only One Is Important:” SARS-CoV-2 has undergone over 350,000 mutations. But only mutations that alter the virus’s biological properties may qualify as strains; otherwise, they are just variants. Researchers then synthesized 106 variants of SARS-CoV-2 that were predicted to modify the virus’s biological attributes and found 68 strains. But each strain comprises <1% of circulating SARS-CoV-2, except for the D614G mutation with >70% prevalence. Thus, out of the 68 characterized strains, only one is clinically relevant. The others may fade away over time as the milder Δ382 strain did.
12. “The Mutations that Caused Covid-19 Reinfection Explained:” A man in Hong Kong contracted Covid-19 for the second time, which is caused by another strain of SARS-CoV-2 that differed from the first by four mutations. Two of these mutations (A222V and D614G) best explain the changes in biological properties and immunogenicity of the virus. While data on the A222V mutation is scarce, at least the D614G mutation does not affect the primary viral structure that vaccines target. And what Covid-19 reinfection mean for our immunity, acquired naturally or artificially (via vaccines), are further discussed.
13. “Rethinking Remdesivir: Is It Really That Effective for Covid-19?:” Increasing data from clinical trials give contradictory results on the efficacy of remdesivir. The overall picture is that remdesivir provides a statistically significant improvement in Covid-19 clinical outcomes but with an uncertain or small effect size. As a result, the cost-effectiveness of remdesivir, which is very expensive, is questioned. And current guidelines say that remdesivir need not be given in cases where it may exacerbate health inequities.

I appreciate your support,
Shin Jie Yong
Editor of Microbial Instincts