The alternative media is justifiably abuzz with a story about the CDC deleting a page on their website admitting that as many as 98 million Americans received polio vaccine contaminated with the cancer-linked monkey virus SV40, with the added twist that although they removed the page sometime after July 11th, a cached version is still available to view online.
Some of the details of the 'disappeared' page read as follows:
Cancer, Simian Virus 40 (SV40), and Polio Vaccine Fact Sheet
- SV40 is a virus found in some species of monkey.
- SV40 was discovered in 1960. Soon afterward, the virus was found in polio vaccine.
- More than 98 million Americans received one or more doses of polio vaccine from 1955 to 1963 when a proportion of vaccine was contaminated with SV40; it has been estimated that 10–30 million Americans could have received an SV40 contaminated dose of vaccine.
- SV40 virus has been found in certain types of cancer in humans, but it has not been determined that SV40 causes these cancers.
- The majority of scientific evidence suggests that SV40-contaminated vaccine did not cause cancer; however, some research results are conflicting and more studies are needed.
- Polio vaccines being used today do not contain SV40. All of the current evidence indicates that polio vaccines have been free of SV40 since 1963.
Plenty of folks are taking notice of the deletion of the page, and for good reason, as it was a relatively high-profile reference on sites like Wikipedia where it was cited three times [footnote 53] on the Polio Vaccines page, under the section "Contamination concerns," in the following paragraph:
SV40 was found to be present in stocks of the injected form of the polio vaccine (IPV) in use between 1955 to 1963. It is not found in the OPV form. Over 98 million Americans received one or more doses of polio vaccine between 1955 to 1963 when a proportion of vaccine was contaminated with SV40; it has been estimated that 10–30 million Americans may have received a dose of vaccine contaminated with SV40. Later analysis suggested that vaccines produced by the former Soviet bloc countries until 1980, and used in the USSR, China, Japan, and several African countries, may have been contaminated; meaning hundreds of millions more may have been exposed to SV40.
Now when you click the citations on Wikipedia taking you to the CDC's website you get the following message:
We can understand why the CDC would want to flush this information down the 'memory hole,' as any indication that vaccines actually cause disease, especially as terrible as cancer, is a public relations nightmare for an agency aggressively expanding its immunization schedule under the auspices of their bulletproof 'safety' and 'efficacy,' as well as looking for public support for legislation that would further limit and even ban vaccine exemptions.
But this "leak" is really only the tip of the iceberg. SV40, which stands for Simian Virus #40, is only one of a wide range of so-called "adventitious" viruses that continue to contaminate vaccine seed stock and substrate (cells used to grow vaccine), which include endogenous retroviruses such as mouse mammary tumor virus, and many which have yet to be identified. SV40 was after all the 40th simian virus identified, and this was 50 years ago. We can only imagine how many hidden disease vectors exist and have been identified by vaccinologists and virologists over the intervening years, but which never made it to the light of day.
Additionally, the information the CDC deleted from its website, is highly misleading. For example, the CDC says:
"SV40 virus has been found in certain types of cancer in humans, but it has not been determined that SV40 causes these cancers."
SV-40 has a well-known mechanism of carcinogenicity. This virus suppresses the transcriptional properties of the tumor-suppressing p53 protein in humans, a gene product that has been described as "the guardian of the genome" because of its critical role in preventing genome instability and cancer initiation. When p53 is disabled, programmed cell death (apoptosis) and cell cycle arrest is rendered dysfunctional, leading to uncontrolled (immortalized) cell proliferation, and tumor formation. Animal research provides experimental confirmation for the tumor-forming properties of SV40, which lends support to viewing the presence of SV40 in various human tumors as a causal connection and not a merely coincidental correlation.         
Also, the CDC's claim that SV40 has not been proven "a cause" is disingenuous, as no cancer can be considered to be a result of a singular cause. SV40 is a well-known cofactor in the pathogenesis of some tumors,  and therefore should not be dismissed or minimized to the point of being perceived irrelevant.
CDC: "All of the current evidence indicates that polio vaccines have been free of SV40 since 1963."
Not so. In 2005, the journal Cancer Research published a study titled, "Some oral poliovirus vaccines were contaminated with infectious SV40 after 1961." The research for the study was prompted by the detection of SV40 in a wide range of human tumors,(3-12) leading the World Health Organization to issue a recommendation in 2000 to test polio vaccines produced after 1961. They found that vaccines from a major eastern European manufacturer (EEVM) contained infectious SV40 which were "produced from early 1960s to about 1978 and were used throughout the world." They used 3 different technical approaches (PCR, transfection, and direct infection of susceptible cell cultures) to confirm the presence of two separate infectious SV40 strains in EEVM.
The researchers expanded on this finding:
The EEVM samples that we tested were produced in 1966 and 1969; therefore, we show that SV40 contaminated some polio vaccines at least until that period. The EEVM vaccine samples we tested ( Table 1) were produced with the same seed virus that was used until 1978, apparently without any further purification to remove SV40. Therefore, it is possible that the EEVM vaccines may have remained SV40 contaminated until 1978 when a new seed was produced. We have no information about this seed virus or vaccines produced from it. Therefore, based on our data, we could not determine the exact time when EEVM vaccines became SV40 free but can suggest that it may have happened in the 1980s when EEVM switched to seed virus stocks provided by the WHO that we found to be free of SV40.