Skip to content
Home » Florida Surgeon General Ladapo is wrong about COVID vaccines

Florida Surgeon General Ladapo is wrong about COVID vaccines

Last updated on January 4th, 2024 at 01:26 pm

Florida Surgeon General, Joseph Ladapo, MD, Ph.D., has claimed COVID-19 vaccines may be contaminated with SV40 virus DNA fragments in an attempt to use his office to make the vaccines appear dangerous. There is nothing that supports his claims.

Furthermore, Peter Marks, MD, Ph.D., director of FDA’s Center for Biologics Evaluation and Research (CBER), strongly refuted Ladapo’s claims. Dr. Marks’ rebuke is based on science and evidence, as opposed to Ladapo’s claims, which seem to be based on political expediency in Florida.

Now, this is not the first time that Ladapo has hit my science radar. Previously, I criticized his complete misuse of the VAERS database to make false claims about the COVID-19 vaccines. So it’s not his first rodeo in COVID-19 vaccine disinformation.

This article will review what Ladapo said and why he is scientifically wrong.

words in dictionary
Photo by Nothing Ahead on

What is Joseph Ladapo claiming?

Ladapo is alleging that “host cell DNA fragments” have been discovered in the Pfizer and Moderna COVID-19 mRNA vaccines in a letter he wrote to the FDA. He questioned whether the shots’ lipid nanoparticles could ferry contaminant DNA into human cells, and whether “the presence of [Simian Virus] SV40 promoter/enhancer DNA may also pose a unique and heightened risk of DNA integration into host cells.”

The appearance of SV40 in vaccines is one of those anti-vaccine tropes that have been circulating for years if not decades. During the 1950s, polio vaccines were developed separately by Jonas Salk (injected, inactivated virus, vaccine) and Albert Sabin (oral, live virus, vaccine). Immunization against polio went back and forth between the two versions of the vaccine, although since the early 1980s, the USA has used the Salk version of the vaccine almost exclusively.

Here is how SV40 got in the polio vaccines:

  • The vaccines were produced using VERO green monkey kidney cell lines. Typically, viruses used in vaccines need to be “grown” in a cell line, because viruses cannot replicate themselves without hijacking a normal cell, and reproduce using that cell’s machinery.
  • In 1959, microbiologist Maurice Hilleman found a monkey virus in both vaccines — it was the 40th simian virus (SV) to be discovered by scientists, so it was given the moniker of SV40 (creativity in naming viruses isn’t important even today). Back in the 1950s, we didn’t have the technology that we do now to screen for contaminants in the growth medium, so the SV40 virus had contaminated the VERO line well before the beginning of production of vaccines. Not all of the VERO cells were contaminated with SV40, although the exact proportion is unknown.
  • Salk’s inactivated virus vaccine, which was treated with formaldehyde (only a tiny amount remains in the vaccine, and let’s not spend time arguing about the “danger” of formaldehyde in vaccines), had very small amounts or possibly none of the SV40 virus. On the other hand, Sabin’s live oral vaccine was heavily contaminated with SV40, because there was no treatment was performed on the vaccine to inactivate the polio virus.
  • Recent studies have shown no credible evidence (here, here, here) that those children who received SV40-contaminated vaccines had an increased incidence of cancer versus unvaccinated children. No plausible evidence suggests that SV40, with or without the polio vaccine, can cause cancer in humans (pdf). A meta-review of published research from the 1960s to 2004 showed no evidence that supported any causal link between SV40 and any cancer. A review of cancers thought to be most associated with SV40 found no evidence to support causality between the virus and cancer. So even if SV40 entered into the bodies of individuals who received the polio vaccine, there is little evidence that it can cause any cancer.
  • Finally, polio vaccines have been SV40-free since 1963 in most advanced countries, although Soviet bloc vaccines were contaminated until the 1980s.

So let me sum this up:

  1. Polio vaccines may have been contaminated with SV40 virus.
  2. Polio vaccines have not been contaminated with the virus for over 60 years.
  3. SV40 virus is not linked to any cancer.

FDA response to Ladapo

The FDA letter went into detail about Joseph Ladapo’s claims, so I’ll just give you the summary.

  1. SV40 or SV40-contaminated cells are not used in the production of COVID-19 vaccines. There is simply no way that SV40 or DNA fragments from SV40 would get into the vaccine.
  2. Dr. Marks added that “it is quite implausible that the residual small DNA fragments located in the cytosol could find their way into the nucleus through the nuclear membrane present in intact cells and then be incorporated into chromosomal DNA.” Making this claim betrays Ladapo’s lack of serious knowledge about how the vaccines work and how DNA and RNA enter the cell. This is the knowledge that a first-year pre-med student would learn.
  3. Marks also said that reproductive toxicology studies have found no evidence of residual DNA fragments getting into reproductive cells, a concern raised by Ladapo in his letter to the FDA.
  4. Even if DNA were found in the vaccines, and there isn’t, let’s just assume there is, the DNA would have zero effect on human cells.

Of course, Ladapo has repeatedly come under fire for his analysis and claims related to the COVID-19 vaccines. He is just another anti-vaxxer with a title after his name but lacks any evidence supporting his disinformation about COVID-19 vaccines.


Michael Simpson
Liked it? Take a second to support Michael Simpson on Patreon!
Become a patron at Patreon!

Discover more from Skeptical Raptor

Subscribe to get the latest posts sent to your email.

Discover more from Skeptical Raptor

Subscribe now to keep reading and get access to the full archive.

Continue reading