Vaccination: a powerful line of defense in cancer prevention

In the field of cancer prevention and control, vaccination is gradually becoming a effective preventive method. With the deepening of medical research, more and more evidence shows that specific vaccines can effectively reduce the risk of some cancers, which brings many benefits to individual health and social public health.

Principle of vaccine prevention of viral-associated cancers

The occurrence of many cancers is closely related to viral infection. For example, human papillomavirus (HPV) infection is a major cause of many cancers, including cervical cancer and anal cancer; Hepatitis B virus (HBV) infection is an important risk factor for liver cancer. The mechanism of action of vaccines is to stimulate the human immune system to produce specific antibodies and immune cells against these viruses by mimicking certain characteristics of the virus. When the body is actually exposed to the virus, the immune system can quickly recognize and eliminate it, thereby preventing viral infection and reducing the risk of cell cancer caused by persistent viral infection.

Significant effects against specific cancers

(1) HPV vaccine and cervical cancer prevention

Cervical cancer is one of the most common malignant tumors in women worldwide. According to the World Health Organization (WHO), there are about 500,000 new cases of cervical cancer and about 270,000 deaths from cervical cancer worldwide every year. Persistent infection of high-risk HPV is necessary for the development of cervical cancer, and HPV16 and HPV18 are responsible for about 70% of cervical cancer cases.

The advent of HPV vaccine has brought revolutionary changes for cervical cancer prevention. Take the bivalent HPV vaccine, for example, which targets HPV16 and HPV18 types. Multiple large-scale clinical trials and real-world studies have shown that bivalent HPV vaccine has 98% to 100% efficacy in preventing HPV16/18-related precancerous lesions in HPV-uninfected women. In some countries and regions with high HPV vaccination rates, such as Australia, the incidence of cervical precancerous lesions among women aged 15-29 years has decreased significantly since the implementation of an HPV vaccination program in 2007. Data from 2017 show an 86% reduction in the incidence of high-grade cervical intraepithelial neoplasia (CIN 2+) among women in this age group compared with pre-vaccination levels.

Here are some statistics on HPV vaccination coverage:

Global data: An estimated 118 million women in countries with HPV immunization programs were enrolled from June 2006 to October 2014, but only 1% were from low - or lower-middle-income countries, according to a 2016 study published in The Lancet Global Health. 47 million women (95% CI, 39 million-55 million) were fully vaccinated, giving an overall population coverage of 1.4% (95% CI, 1.1%-1.6%); 59 million women (48 million to 71 million) have received at least one dose of vaccine, giving an overall population coverage of 1.7% (1.4% to 2.1%). In more developed regions, 33.6% (95% confidence interval 25.9%-41.7%) of women aged 10-20 years were fully vaccinated compared to 2.7% (1.8%-3.6%) in less developed regions.

China Data :

The whole country: According to the National Health Commission in October 2024, since 2021, 11 provinces such as Guangdong, Hainan, Fujian, Jiangsu, Jiangxi, Chongqing, Tibet, Zhejiang, Shandong, Hubei, Guangxi, and cities such as Zhengzhou, Ordos and Chengdu have included HPV vaccination in the government's practical projects for the private sector. The free HPV vaccination policy has covered about 40% of school-age girls in the country.

Hainan Province: In 2022-2024, a total of 180,000 school-age girls in Hainan will receive HPV vaccination, and the vaccination rate of the target population is over 90%. Hainan is one of the first provinces in China to achieve full coverage of free HPV vaccination. In 2024, Haikou had provided free HPV vaccination services for 106 000 school-age girls, and the vaccination coverage of the target population had reached 91.5%.

(2) Hepatitis B vaccine and liver cancer prevention

Liver cancer is one of the cancers with high morbidity and mortality worldwide. In China, about 80% of liver cancer patients are related to HBV infection. Chronic HBV infection can lead to liver inflammation and fibrosis, and then develop into cirrhosis and liver cancer.

Since hepatitis B vaccine was included in the management of planned immunization in 1992, hepatitis B vaccination has achieved remarkable results. According to data from the Chinese Center for Disease Control and Prevention, from 1992 to 2014, the prevalence of hepatitis B surface antigen (HBsAg) in children under 5 years old in China decreased from 9.67% to 0.32%. Due to hepatitis B vaccination, about 28 million children have been infected with hepatitis B virus and about 8.6 million chronic hepatitis B cases have been reduced. Approximately 430 000 cases of cirrhosis and liver cancer due to hepatitis B virus infection have been reduced.