Vaccination is the best protection against infections caused by HPVs and their complications.
HPV vaccines (Cervarix® and Gardasil® 9) protect against HPV 16 and 18, which are responsible for most HPV-related cancers, such as cancer of the cervix, vagina, vulva, penis, anus and throat.
Gardasil® 9 also protects against genital or anal warts, which are caused by infections from certain types of HPVs. In people who have not been vaccinated against HPV, warts are the most common sexually transmitted infections diagnosed in Canada.
Very often, people infected with HPV do not have symptoms. A person can therefore be infected without knowing it.
What are the vaccines made from
HPV vaccines stimulate the immune system to prepare antibodies against these viruses. They do not contain viruses or parts of viruses. They are made from proteins that mimic the viral envelope and are unable to infect the person who is given the vaccine. In other words, these vaccines cannot transmit a HPV infection.
Like many other vaccines, HPV vaccines contain an adjuvant, which is used to increase the immune system’s response to the vaccine. HPV vaccines do not contain any preservatives, latex, antibiotics, thimerosal or mercury.
HPV vaccines are developed in accordance with the usual process prescribed by Health Canada. This process regulates and oversees vaccine research, manufacturing, licensing, efficacy and safety. All vaccines must go through this process in order to be distributed in Canada.
The manufacturer of the Cervarix® vaccine has not taken steps for this vaccine to be licensed in Canada for use in boys. It is therefore approved for use in girls and women age 9 to 45. However, scientific data, including data from a study conducted in Québec, shows that this vaccine is safe and produces a similar immune response in boys and girls. In addition, in Europe this vaccine is approved for use in boys and girls age 9 or older. Norway has been using two doses of the Cervarix® vaccine for both boys and girls since September 2018.
For more information, consult How vaccines work.
Number of doses required
Two doses of the vaccine are required for the best possible protection.
For people under 18 years of age, one dose of Gardasil® 9 followed by one dose of Cervarix® will produce a sufficient immune response.
Based on various studies, experts believe that these two vaccines will produce a stronger immune response to HPV types 16 and 18 than two doses of Gardasil® 9. HPV 16 is responsible for most HPV-related cancers, especially cancers that affect men. Furthermore, these two vaccines provide immunity against the seven other types of HPV targeted by the Gardasil® 9 vaccine.
For people aged 18 or older, two doses of Gardasil® 9 produce a sufficient immune response. Despite lower antibody levels than in younger people, a high level of efficacy has been demonstrated in people vaccinated in adulthood. Two doses of Gardasil® 9 administered at least 6 months apart are just as effective as a 3-dose schedule.
These vaccines are more effective when the person being vaccinated has never had a HPV infection. Since the infection usually occurs in the first years of sexual activity, the vaccine should ideally be given before the person becomes sexually active. These vaccines are nonetheless indicated for people who have already had a HPV infection or lesion.
Vaccination is not a substitute for cervical cancer screening.
Duration of protection
These vaccines provide protection against HPV infections, precancerous lesions and warts for at least 14 years.
Studies are being conducted around the world to evaluate long-term protection, but it is believed that it should last several decades. There is no indication that a booster dose is necessary at this time.
Benefits of HPV vaccination
Vaccination has been proven effective in reducing, or even eliminating, some serious diseases. This is also true of HPV vaccination.
In many countries, a significant decrease in precancerous cervical lesions and warts has been seen since vaccination was introduced. A study conducted in Québec also showed a significant decrease in the number of cases of warts since the introduction of vaccination, particularly in groups of girls targeted by vaccination.
Another study conducted in Québec showed that rates of infection with the types of HPV targeted by the vaccine were much lower in vaccinated women than in non-vaccinated women. Furthermore, these types of HPV were nearly absent in women who had been vaccinated before they became sexually active.
Although there is usually a long period between HPV infection and the development of cancer, studies have already started to show that the vaccine is highly effective against cervical cancer.
For men who do not have a HPV infection when they vaccinated, the vaccine’s efficacy rate:
- Is 90% for preventing warts
- Is almost 80% for preventing precancerous or cancerous lesions of the genitals, anus or throat
However, the vaccine’s efficacy rate is lower in people who are already infected when they are vaccinated.
Recent studies show that the vaccine could, however, prevent the reappearance of anal lesions in men under the age of 26 who are already infected with one of the HPV types targeted by the vaccine at the time of vaccination. No data are available for men over 26 years of age.
Symptoms after vaccination
Some symptoms may be caused by the vaccine, e.g. redness at the injection site. Other problems may occur by chance and are not related to the vaccine, e.g. cold, gastro, headache.
HPV vaccines are safe. Most symptoms or reactions are benign and do not last long.
|Known reactions to the vaccine
In most cases
The Cervarix® vaccine causes a little more pain, redness and swelling at the injection site than the Gardasil® 9 vaccine.
To date, over 300 million doses of HPV vaccines have been administered worldwide. According to current scientific data, no serious or unexpected problems are associated with these vaccines. No link has been found between this vaccine and certain serious diseases or deaths.
The side effects of HPV vaccination are being studied worldwide. The Ministère de la Santé et des Services sociaux monitors side effects of the HPV vaccine. As for all immunization programs, the monitoring of side effects is done through the Programme de surveillance passive des effets secondaires possiblement reliés à l’immunisation (ESPRI).
To find out more, go to the Safety of the human papillomavirus (HPV) vaccine page.
What to do after vaccination
Tips to follow immediately following vaccination
Wait 15 minutes before leaving premises where vaccine is received. If an allergic reaction occurs, the symptoms will appear a few minutes after the vaccination.
If you feel side effects, immediately inform the person giving the vaccine. That person will be able to treat you immediately.
Tips to follow at home
If you experience redness, pain or swelling at the injection site, apply a cold, damp compress on it.
Use medication for fever or discomfort if needed.
When to seek medical help
See a doctor if one of the following applies to you:
- You experience serious and unusual symptoms
- Your symptoms get worse instead of improving
- Your symptoms last over 48 hours
Last update: January 18, 2023