04/2023 Issue: What’s New This Month About Vaccine Safety and Arcturus Variant

A newsletter providing a short account of the articles published in the previous month.

Hi everyone! It’s time for me to send another monthly update on what has been published in Microbial Instincts, an independent publication about infectious diseases and vaccines, in April 2023. As usual, here is a short list (friend-linked, no paywall) that I hope will keep you more scientifically informed:

Vaccines

• Are Covid-19 Vaccines Safe For Cancer Patients? A Critical Analysis: Almost half of cancer patients hesitate about getting the Covid-19 vaccine, mostly due to safety uncertainties. Such concerns are warranted given the lack of randomized controlled trial (RCT) data (as RCT typically excludes immunocompromised patients) and theoretical concerns about vaccines accelerating cancer progression. I addressed these issues in depth, concluding that cases of vaccine-related cancer progression are too rare that they are statistically undetectable in cohort studies (Fig 1).

Figure 1. Available safety data of Covid-19 booster shots in cancer patients. Source: Shin Jie Yong.

• Vaccine Safety Roulette: Can the Batch Determine Your Vaccine Safety?: A new Danish study produced an interesting analysis — that smaller vaccine batches were associated with high adverse events for unclear reasons (Fig 2). I then discussed the implications of this study, i.e., what it means for vaccine safety. I also described how quality control and batch recall of vaccines work. In the end, like any manufacturing process, vaccine quality control is not perfect either. But a new technology — water proton nuclear magnetic resonance — might overcome this limitation and improve vaccine quality control.

Figure 2. The number of suspected vaccine adverse events (SVAEs) occurring after Pfizer’s mRNA vaccination in Denmark between 27 December 2020 to 11 January 2022, according to the number of doses per batch. Source: Schmeling et al. (2023).

• Vaccination Overload: Is There a Limit to How Many Shots You Can Get?: One of the leading reasons for parental vaccine hesitancy is whether multiple concurrent vaccinations overwhelm the immune system. Children nowadays get as many as 20 vaccines within the first two years of life (Fig 3), so it’s unsurprising to question if these many shots are safe. But thankfully, they are safe. Theoretically, the immune system can handle up to 10,000 vaccines at any time. And human RCTs and observational cohort studies have noted no safety concerns when receiving vaccines simultaneously than at different times.

Figure 3. The number of vaccines and the possible number of vaccinations at a single visit between 1900 to 2000. Source: Offit et al. (2002).

Arcturus variant

• Arcturus: The Coronavirus Variant That Is Taking Over the World: Milton Simba Kambarami provided an overview of the latest Omicron subvariant, Arcturus that has been spreading much more rapidly, even faster than the Kracken subvariant, at least in India. Milton then draws on this expertise as an evolution bioinformatician to help us better understand the evolution and biochemistry of SARS-CoV-2 evolution. He further ran some statistical tests to show us that Arcturus cases have no age-specific pattern but appear to infect men preferentially (Fig 4).

Figure 4. The number of individuals per gender infected by the Arcturus variant. The difference, though small, is statistically significant. Source: Milton Simba Kambarami

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