Sign in

Shin Jie Yong
Aiming to improve scientific literacy in this age of information overload and mis/disinformation, especially on controversial and polarizing topics.
Image from

It’s rather uncomfortable to admit that vaccines have health risks, however safe they are in the vast majority. For influenza vaccines, febrile seizures (convulsions), Guillain–Barré syndrome (autoimmune nerve disorder), and anaphylaxis (severe allergic reaction) can happen. For Covid-19, anaphylaxis can occur from many vaccines, severe and fatal blood clots plus low platelets from AstraZeneca and J&J DNA vaccines, and mild-to-severe heart inflammation from Pfizer and Moderna mRNA vaccines.

Thankfully, the risks of these vaccine adverse events are very low and don't outweigh the benefits that vaccines provide in most situations. Still, it doesn’t hurt to understand them further to see…

Image by

It has been almost a year since the BioNTech-Pfizer’s and Moderna’s mRNA vaccines received emergency use authorization (EUA) from the Food and Drug Administration (FDA) for public use amidst the Covid-19 pandemic in December 2020. These two vaccines are the earliest ones we started using, so they have also been studied very closely.

At present, the FDA has given the first full approval for Pfizer’s mRNA vaccine. Three massive studies on mRNA vaccine safety were also published during the past month, which have made important and somewhat unpleasant discoveries. Let’s see what they are with a critical eye.

1. Data from Israel (Pfizer’s mRNA vaccine)

In a…

Image adapted from

Amidst the push for global vaccination to end the Covid-19 pandemic, we have recently discovered the potential of hybrid immunity, the synergistic combination of different forms of immunity. There has probably never been a time where we study immunity so fiercely as the last 12 months. Believe it or not, there are only six hits on hybrid immunity (which are not even related to vaccines) in PubMed, a biomedical literature database, as of today. So, let’s see what hybrid immunity has to offer.

Natural vs. vaccine-induced immunity (in the context of SARS-CoV-2)

Immunity means resistance to a pathogen or infectious disease. This resistance comes from memory the immune system…

Hi all! Here’s another monthly update from me, the editor of Microbial Instincts, an independent publication on Medium. (It’s run by a student, not a professional, but at least he’s politically uninvolved.) As usual, articles (friend linked) published in the past month — on coronavirus evolution, vaccines, and other aspects — are described briefly, which I hope will keep you more informed:

SARS-CoV-2 evolution

Cloth mask (pink color)
Image adapted from

In August 2021, Senator Rand Paul of Kentucky said that cloth masks don’t prevent infection from SARS-CoV-2 (that causes Covid-19) in a YouTube video. But Youtube banished the video and suspended Mr. Paul for a week. I got this news from Joe Duncan, a veteran independent writer.

“The New York Times blasted Rand Paul for saying that too but I think he might actually be right here, considering the science I’ve seen,” he told me. “Surely, a cloth mask is better than nothing, but how much better? …

Image by Sten Søndergaard from Pixabay

There’s an uncanny observation that the SARS-CoV-2 variants of concern (VOCs)— Alpha, Beta, Gamma, and Delta — arose soon after the vaccine clinical trials in the same countries. As a result, some have speculated that the trials instigated the evolution of those VOCs. Let’s see if they have a point.

Variants of concern (VOCs) emergence and vaccine clinical trials

The World Health Organization (WHO) defines VOCs as mutated SARS-CoV-2 that has one or more of the following features: (i) more transmissible, (ii) more virulent that causes more severe disease, or (iii) more problematic in terms of making public health measures— such as diagnostic tests, drugs, or vaccines — less…

Image by

A thought came to my mind: What if a population of unvaccinated and vaccinated hosts creates a selection pressure that selects for the evolution of more dangerous variants than Delta? Let’s take a critical look at whether this concern is justified and see what’s happening and what might happen as we engage in an evolutionary arms race with SARS-CoV-2.

(Note: variants mentioned herein belong to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes Covid-19.)

Delta’s current data

Following the World Health Organization’s (WHO) new naming system, the variant under the lineage B.1.617.2 — first discovered in India in December 2020 —…

Hi everyone! Here’s another monthly issue from Microbial Instincts, an independent publication about infectious diseases on Medium (that’s managed by someone who’s doing it as a hobby). As usual, articles (friend linked) published in July 2021 are briefly described, which I hope will keep you more scientifically informed on topics that matter.

Vaccine safety

Source: iStock

Ivermectin is oddly popular among health officials and the public alike in some countries —notably Latin America, South Africa, and Indonesia — as the ‘cure’ or ‘miracle drug’ against Covid-19. The price of ivermectin has skyrocketed as a result, even more so in the black market. But the World Health Organization (WHO) and Food and Drug Administration (FDA) have not approved the use of ivermectin to treat Covid-19 outside clinical trials.

As such, there are two main schools of thought about this:

  • Ivermectin is ineffective or not very effective against Covid-19. …

Image adapted from

Vaccine safety is a polarized topic. Many either stay on the side of safe or unsafe vaccines when the reality isn’t so black and white. A vaccine is a type of drug. Like antibiotics, birth control pills, statins, and antidepressants, they all come with risks and hopefully more benefits.

That said, this article will examine if there’s any truth or validity in the claims that Covid-19 vaccines are unsafe based on what has been reported to the vaccine adverse event reporting system (VAERS), a passive surveillance system that monitors vaccine safety in the U.S. beyond clinical trials.

The unsafe Covid-19 vaccines narrative

In the rather…

Shin Jie Yong

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store