Understanding HPV Vaccine: Is It Really Safe? - Dr Sredharan M
Cervical cancer develops from the lowermost portion of the uterus, the part which connects the uterus to the vagina. Over 80% of cervical cancer is caused due to infection by Human papillomavirus (HPV) which is a sexually transmitted viral infection.
It is the most common sexually transmitted viral infection, and most men and women who are sexually active are infected by this virus. About 10% of these individuals develop persistent infection. A persistent infection over 5-15 years leads to cancer development.
Understanding HPV Virus
HPV virus is a DNA virus. Once infection happens, the virus incorporates its genome into the host cells. When the host cells multiply, the viral genome is also replicated and passed on to the daughter cells, thereby causing persistent infection.
There are over a hundred different types of HPV. Depending on their ability to cause cancer, they can be classified as high-risk strains or low-risk strains.
Most of the cervical cancers are caused by the high-risk strains HPV 16 and 18. The other two significant strains are 6 and 11 which are low-risk strains. These strains are responsible for genital wart infection. Apart from cervical cancer, HPV causes 5 other cancers – anal cancer, oropharyngeal cancer, penile cancer, vaginal cancer, and vulval cancer.
Many people with HPV infection do not develop symptoms. But they can still infect other people. The most common symptoms are the development of warts in the genital area, which appear as raised bumps in the skin. Some may also experience itching.
Currently, there is no treatment for HPV infection. Vaccination is the best way to prevent HPV infection. Vaccination can prevent over 97% of cervical cancer and genital warts. It also gives protection against the above-mentioned cancer types. HPV vaccine is recommended for both boys and girls.
The HPV vaccine dose is 0.5ml per shot. HPV vaccines are typically administered in 2 doses at a 6-12-month interval between 9-14 years of age. Children who missed the vaccination before their 15th birthday can also get vaccinated. A 3-dose regimen is recommended at 0,1 and 6 months interval between age 15-26 years.
It is important to note that the vaccine acts by preventing HPV infection and is not useful in those who already have HPV infection. So, the vaccine should be given before the commencement of sexual activity. The immunity developed after HPV vaccine is life long and booster doses are not needed.
For children younger than 9 years of age, the safety and efficacy are not yet established. Recently, the vaccination is approved for women till 45 years of age. Although not as effective as vaccination in young girls, vaccination in older women has been shown to reduce the risk of cervical cancer. They act by preventing the infection against the HPV strains which the women aren’t still exposed to.
Are HPV Vaccines really safe?
HPV vaccines are non-infectious recombinant vaccines, which means they are prepared from virus-like particles (VLP) which are tiny proteins that resemble the outside of the virus. They do not contain live or dead viruses or viral DNA.
Hence, HPV vaccines are tolerated well, and side effects are usually mild. Injection site pain, redness, fever, muscle and joint pain, headache, and fatigue can happen and are usually self-limiting.
Some teens experience fainting after vaccination. Severe allergic reaction/anaphylaxis is a rare complication occurring in 1 per 10,00,000 doses. They usually occur within 15 minutes of injection.
Hence, after administration of the vaccine, it is common for the health worker to keep the children under observation for 15 minutes before sending them home. People who are allergic to yeast, those who had allergic reactions to previous vaccine doses, and pregnant women should not take the vaccine.
HPV vaccines should be stored in the refrigerator at a temperature of 2-8 degrees Celsius. They should not be frozen and should be stored away from sunlight. The cold chain should be maintained properly to preserve its efficacy. Once removed from refrigeration or icebox, they should be shaken well and should be administered without much delay.
The Serum Institute of India started manufacturing of indigenously developed CERVAVAC vaccine. It is a quadrivalent vaccine that protects against the 4 most common strains in India 6,11, 16, and 18. The US-made HPV vaccine GARDASIL-9 on the other hand gives protection against 9 strains of HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58. CERVAVAC is reported to be as effective and immunogenic as its US counterpart.
Cervical cancer, predominantly caused by Human Papillomavirus (HPV) infection, poses a significant global health challenge. However, the advent of HPV vaccines has provided a groundbreaking solution for prevention. By targeting high-risk HPV strains, these vaccines offer remarkable efficacy in preventing not only cervical cancer but also genital warts and other HPV-related cancers.
Emphasizing vaccination before the onset of sexual activity, particularly among adolescents, is crucial for maximizing effectiveness. Moreover, recent expansions of vaccination recommendations to older age groups, coupled with government initiatives to incorporate HPV vaccination into national immunization schedules, signify a concerted effort towards comprehensive disease prevention.
Alongside vaccination, education, and awareness campaigns play a vital role in promoting vaccine uptake and fostering a culture of preventive healthcare. Through sustained efforts at individual, community, and governmental levels, we can envision a future where cervical cancer becomes a preventable disease, sparing countless lives and alleviating the societal burden of this devastating illness.
Disclaimer: The views expressed in this article are of the author and not of Medical Dialogues. The Editorial/Content team of Medical Dialogues has not contributed to the writing/editing/packaging of this article.
