HPV vaccines 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.
The nonavalent vaccine (HPV-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.
For people under 20 years of age, one dose of VPH-9 will produce a sufficient immune response. People with weakened immune systems will need additional doses, according to a special schedule.
Based on a number of high-quality studies and the position of the World Health Organization, experts believe that this single-dose HPV-9 schedule offers high protection similar to that induced by a 2-dose schedule in this age group.
For people aged 21 or older, two doses of VPH-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 VPH-9 administered at least 6 months apart are just as effective as a 3-dose schedule. People with weakened immune systems will need additional doses, according to a special 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.
These vaccines provide protection against HPV infections, precancerous lesions and warts for at least 11 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.
For women
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
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.
The nature and frequency of known reactions to the HPV vaccine
Frequency
Known reactions to the vaccine
In most cases (more than 50% of people)
Pain at the injection site
Very often (less than 50% of people)
Redness or swelling at the injection site
Often (less than 10% of people)
Itching at the injection site, fever
To date, over 500 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).
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 healthcare professional if one of the following applies to you: