HPV Strains



The Human Papilloma Virus (HPV) is the cause of both genital and non-genital warts. This is a very common family of viruses.  There are actually more than 100 different strains of HPV.  Of these, approximately 30 exist in the genital area and can cause genital warts (condyloma acuminata).  These 30 strains can be further broken down to “high” and “low” risk strains.



High risk strains may show up in a Pap smear and may rarely develop into cancer.  There are approximately 13 high-risk strains of HPV. Two strains (16 & 18) are believed to cause about 70% of all cervical cancer.

Low risk strains can sometimes cause changes in a Pap smear, but do not progress to cancer. Two of the low risk-risk strains (6 and 11) are most likely to cause genital warts.

There are 40 strains of HPV that can affect the anal and genital tracts and these are further divided into low risk and high risk strains.


Thirteen strains are considered high risk, or more likely to progress to high grade lesions (HSIL, CIN 2 or 3) and possibly cancer, if not cleared by the immune system. These strains are: 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68. Strains 16 and 18 are by far the most common types, and one or both are present in approximately 70% of cervical cancers worldwide. Despite this strong link, only a very small percentage of high risk HPV infections will ever become invasive cancer (estimated at 2%). The time between initial exposure and the development of cancer can vary from months to years, but the average time is thought to be 15 years. Unfortunately, the high risk HPV strains do not usually cause any symptoms to alert someone that they have the infection. The low risk strains are not considered a risk for cervical cancer, but they can cause low grade lesions (CIN 1) and several of these strains can cause genital warts.

GARDASIL [Human Papillomavirus Quadrivalent (Types 6, 11, 16, and 18) Vaccine, Recombinant]


GARDASIL is a vaccine indicated in girls and women 9 through 26 years of age for the prevention of the following diseases caused by Human Papillomavirus (HPV) types included in the vaccine:

Cervical, vulvar, and vaginal cancer caused by HPV types 16 and 18

Genital warts (condyloma acuminata) caused by HPV types 6 and 11

And the following precancerous or dysplastic lesions caused by HPV types 6, 11, 16, and 18:

Cervical intraepithelial neoplasia (CIN) grade 2/3 and Cervical adenocarcinoma in situ (AIS)

Cervical intraepithelial neoplasia (CIN) grade 1

Vulvar intraepithelial neoplasia (VIN) grade 2 and grade 3

Vaginal intraepithelial neoplasia (VaIN) grade 2 and grade 3

GARDASIL, Human Papillomavirus Quadrivalent (Types 6, 11, 16, and 18) Vaccine, Recombinant, is a non-infectious recombinant quadrivalent vaccine prepared from the purified virus-like particles (VLPs) of the major capsid (L1) protein of HPV Types 6, 11, 16, and 18. The L1 proteins are produced by separate fermentations in recombinant Saccharomyces cerevisiae and self-assembled into VLPs. The fermentation process involves growth of S. cerevisiae on chemically-defined fermentation media which include

vitamins, amino acids, mineral salts, and carbohydrates. The VLPs are released from the yeast cells by cell disruption and purified by a series of chemical and physical methods. The purified VLPs are adsorbed on preformed aluminum-containing adjuvant (Amorphous Aluminum Hydroxyphosphate Sulfate). The quadrivalent HPV VLP vaccine is a sterile liquid suspension that is prepared by combining the adsorbed VLPs of each HPV type and additional amounts of the aluminum-containing adjuvant and the final

purification buffer.

GARDASIL is a sterile suspension for intramuscular administration. Each 0.5-mL dose contains approximately 20 mcg of HPV 6 L1 protein, 40 mcg of HPV 11 L1 protein, 40 mcg of HPV 16 L1 protein, and 20 mcg of HPV 18 L1 protein.

Each 0.5-mL dose of the vaccine contains approximately 225 mcg of aluminum (as Amorphous Aluminum Hydroxyphosphate Sulfate adjuvant), 9.56 mg of sodium chloride, 0.78 mg of L-histidine, 50 mcg of polysorbate 80, 35 mcg of sodium borate, < 7 mcg yeast protein/dose, and water for injection.

The product does not contain a preservative or antibiotics.

CERVARIX® PRODUCT INFORMATION  Human Papillomavirus Vaccine Types 16 and 18

(Recombinant, AS04 adjuvanted)


CERVARIX contains recombinant C-terminally truncated L1 proteins from human papillomavirus (HPV) type-16 and type-18 each assembled as virus-like particles (VLPs)…

The HPV-16 and HPV-18 L1 antigens are prepared by recombinant DNA technology using a Baculovirus expression system in Trichoplusnia ni cells.

HPV-16 and HPV-18 L1 antigens in CERVARIX are adjuvanted with AS04. This AS04 adjuvant system comprises aluminium hydroxide (Al(OH)3) and 3-O-desacyl-4’-monophosphoryl lipid A (MPL). The MPL within AS04 enhances the initiation of the immune response through the activation of innate immunity, leading to an improved cellular and humoral adaptive immune response.

Each 0.5ml dose of CERVARIX contains 20 micrograms each of HPV-16 L1 and HPV-18 L1 proteins, 0.5 milligrams of Al(OH)3 and 50 micrograms of MPL. CERVARIX also contains sodium chloride (NaCl) 4.4 mg, sodium phosphate – monobasic (NaH2PO4.2 H2O) 624 micrograms and water for injection as excipients. CERVARIX does not contain a preservative.

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