Contents
Two vaccines that can prevent HPV infections
Vaccines to prevent
Gardasil and Cervarix are prophylactic vaccines, which means that their role is to prevent infections caused by certain strains of HPV, not to treat them. They are therefore of no use to people who are already infected.
The two vaccines immunize against strains 16 and 18, considered highly carcinogenic: alone, they are responsible for 70% of cases of cervical cancer.
Cancer and condyloma With HPV vaccination, one case of cervical cancer would be avoided for every 324 girls vaccinated, experts say. To prevent one case of genital warts, eight girls should be vaccinated2. |
According to studies carried out so far, these vaccines are very effective in protecting women against these specific strains of HPV. These studies are based on data accumulated over five and a half years for Gardasil and six years for Cervarix.2. Manufacturers continue to monitor changes in their long-term effectiveness.
In addition, recent research suggests that Gardasil and Cervarix could also protect women against other types of HPV at high risk of cancer, by a “crossover” effect.
Special features of vaccines
The Gardasil vaccineMC
Manufactured in the United States, Gardasil is a so-called “quadrivalent” vaccine, which means that it immunizes against four strains of HPV: types 16 and 18, at high risk of cervical cancer; then types 6 and 11, associated with 90% of condyloma cases which rarely lead to cancer. Vaccination requires three doses, spread over six months.
Not for pregnant women GardasilMC is not recommended during pregnancy due to insufficient data on its safety in pregnant women. Also, it is recommended to postpone, after childbirth, the administration of subsequent doses of vaccines, when a woman becomes pregnant after the start of vaccination.3. |
According to studies conducted by the manufacturer, in girls and women only, Gardasil is 99% effective against infections and 95% against the formation of precancerous lesions associated with strains 16 and 18 of HPV3. Trials are underway to measure the effect of this vaccine in men.
In addition, the vaccine would protect 99% against genital warts caused by HPV types 6 and 11. These warts – or condylomas – are common in young adults.3.
Finally, a more recent study indicates that the vaccine could offer “cross-protection”4 against other types of HPV at high risk of cancer, namely strains 31, 33, 45, 52 and 585.
Strains 33 and 45 represent the third and fourth types of HPV most commonly associated with cervical cancer.
The Cervarix vaccinesMC
Made in Belgium, CervarixMC is a so-called “bivalent” vaccine because it immunizes against two types of HPV, strains 16 and 18.
Administration of Cervarix requires three doses, over a period of six months.
According to the manufacturer, Cervarix is 100% effective against infections and 95% against the formation of precancerous lesions associated with strains 16 and 18 of HPV3.
This vaccine, too, could offer cross-protection against at least two other strains (31 and 45) of HPV at high cancer risk, according to GlaxoSmithKline.
Useful vaccines, but not a panacea Because 30% of cervical cancer cases are attributable to strains of HPV other than types 16 and 18, vaccination cannot completely eliminate the risk of infection. Whether or not you are vaccinated against HPV, it is still important to get tested regularly for cervical cancer. |
Adverse reactions
HPV vaccination can be accompanied by some side effects, most of them mild and short-lived, according to manufacturers6 :
- Pain, swelling, stinging, or redness at the injection site
However, some effects deserve to be considered carefully:
- Fever
- Cough
- Difficult or noisy breathing
- Breathless
- Tightness in the chest
Since the studies lasted five and a half years for Gardasil and six years for Cervarix, the efficacy and long-term side effects are not yet known.