What’s old is new again. SV40, a simian virus that raised some concern about cancer once upon a time, is now being found in mRNA vaccines, according to a Japanese report on Twitter.

SV40 is a virus found in monkey kidneys that can potentially cause cancer in humans via tumor (T) antigens. Unfortunately, batches of the polio vaccine became contaminated with SV40, and the methods used to inactivate the poliovirus did not reliably inactivate SV40. Importantly, epidemiological studies have found no increased risk of cancer in those who received these vaccines.

Since then, a promoter gene (a DNA sequence that starts RNA transcription) of SV40 has been found to promote a high level of gene expression for producing proteins in mammalian cells and has been used in developing DNA vaccines. The process uses just the promoter gene and not the virus itself or any part of the DNA sequence that encodes for the T antigen of SV40.

Right now, no evidence exists that mRNA COVID vaccines contain SV40 genes, aside from a single paper that has claimed to sequence the SV40 promoter gene from the Pfizer vaccine.

Twitter is a-twitter with claims that COVID vaccines cause serious adverse events at a rate of 1 in 800 and increase your risk of death.

The British cardiologist makes these claims by citing a paper authored by a member of the Public Health Integrity Committee formed by Ron DeSantis and overseen by surgeon Joseph Ladapo. and an AIDS denier.

The paper claims that the Pfizer and Moderna vaccines lead to an excess risk of serious adverse events. But Table 2 of the paper shows that in almost every category for both risk difference and risk ratio, the confidence interval was 0, essentially stating that statistically, “no difference was observed.” Multiple peer-reviewed studies have shown that serious adverse events from the COVID vaccine are rare, and the benefits of vaccination outweigh its risks.

While wildly overstating the number of serious adverse events from the COVID vaccine, the cardiologist also falsely conflates the COVID vaccine with the 1976 swine flu and RotaShield vaccines and their withdrawal from the market. The decision to withdraw these vaccines was not exclusively based on adverse events.

These decisions also weigh vaccine benefits versus risks. In the two cases of withdrawn vaccines, the vaccine’s benefits did not outweigh the risks. Conversely, the life-saving benefits of the COVID vaccine vastly outweigh the rare risks of an adverse event.

A doctor of English literature has posted a really long video accusing the CDC of knowing the COVID vaccine causes miscarriage and neonatal death, but they told pregnant women to get vaccinated nonetheless.

In clinical trials, an adverse event is anything negative that happens during the study period that may or may not have anything to do with the vaccine. Adverse events from maternal exposure include anything negative that occurred before, during, or after pregnancy, regardless of whether the vaccine was involved at all.

Estimates show that up to 30% of pregnancies end in miscarriage, including some before the pregnancy was known. The number of miscarriages during Pfizer’s clinical trials was well within that threshold. The same holds true for all pregnancy-related adverse events in the study.

Dr. Wolf also lists a number of adverse events occurring in babies exposed to breastmilk of those vaccinated while breastfeeding. Among the vomiting, lethargy, and myriad other adverse events, she also mentioned roseola, a contagious viral illness. Neither the COVID vaccine nor trace amounts of mRNA in breastmilk can cause this viral illness. Only a virus can do that.

The point of collecting adverse event data during trials or through databases such as VAERS is to compare the number of events that happen to those who have been vaccinated and the number of these events that occur in the general population or those not involved in the clinical trials. These systems have shown the COVID vaccine to be safe during pregnancy and breastfeeding.

Getting COVID during pregnancy is risky. Being infected while pregnant makes you 4 times more likely to be admitted to an intensive care unit, 15 times more likely to be ventilated, and 7 times more likely to die compared to people who didn’t get COVID during pregnancy.