Human papillomavirus (HPV) is the most common sexually transmitted infection in the US. Although most genital HPV infections are harmless, at least a dozen types can lead to cancer. Strains 16 and 18 cause an estimated 70% of cervical cancers and represent two of nine strains covered by the HPV vaccine.

In an analysis published in the Centres for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report in late March, Rosenblum and colleagues found that the US’s HPV vaccination programme has led to declines in infections among both vaccinated and unvaccinated women and girls.

GlobalData epidemiologists expect these declines in infection will translate to decreases in associated cancers, including cervical cancer, in the US.

Rosenblum and colleagues used data from the National Health and Nutrition Examination Survey (NHANES), an ongoing CDC national survey, through 2018 to examine HPV prevalence among vaccinated and unvaccinated women.

They found that the prevalence of the strains targeted by the vaccine was 88% lower among females aged 14-19 years from 2015 to 2018 compared with the pre-vaccine era (2003 to 2006), and 81% lower among females aged 20-24 years.

Prevalence was also lower among unvaccinated females, suggesting a strong herd immunity effect. These findings accounted for race, ethnicity and potential changes in sexual behaviour over the study period.

GlobalData epidemiologists forecast that the diagnosed incident cases of cervical cancer will increase in the US, exceeding 14,000 cases in 2028 (as shown by the graph below).

But as HPV infection prevalence will continue to decrease due to the vaccination efforts, a corresponding decline in new cases of cervical cancer will probably follow.

The number of incident cases may, therefore, be lower than expected for the latter part of the forecast, although it may take some time to see the impact of HPV vaccination on cervical cancer rates because of the 15-20 year latency between infection and cancer development.

In the US, HPV vaccination is recommended for children aged 11-12 years. For adults who were not previously vaccinated, catch-up vaccination is recommended up to age 26 years.

While GlobalData epidemiologists recommend continued monitoring of trends in the prevalence of HPV and associated cancers, the evidence currently available suggests that the vaccine is an effective tool for the primary prevention of cancer.

Hearing disorders are a common cause of disability and affect an estimated 14% of the world’s population, according to the World Health Organization (WHO). These disorders may occur from birth or gradually develop over time.

Factors that can increase a person’s susceptibility to hearing disorders include genetic predispositions, advanced age, frequent exposure to loud noises and some infectious diseases.

Measles, rubella and meningitis are examples of infectious diseases that can lead to hearing loss. A lack of access to vaccines that prevent these diseases remains a major obstacle for millions of people living in impoverished environments around the world. In recent years, however, measles outbreaks have even affected developed countries such as the US, UK, New Zealand and Israel.

Reluctance or refusal to receive vaccinations against infectious diseases is becoming a widespread issue in communities where distrust of scientific information is prevalent. Reasons for vaccine hesitancy include the belief that vaccines are harmful or ineffective in preventing the contraction of contagious diseases.

Hearing-related health consequences of infectious diseases can be caused by inflammation of the eardrum and damage to the auditory nerve. The physical symptoms of hearing loss are not the only source of distress for patients. Common psychosocial difficulties include loneliness, depression and anxiety.

These issues are often caused by the inability of sufferers to communicate with other people. Children with untreated hearing loss may suffer from a decreased ability to complete schoolwork and develop problems with socialising with peers.

Families who fail to adhere to childhood immunisation programmes are punished in some countries, but mandatory vaccination policies are difficult to enforce and can cause further distrust of healthcare services and medical professionals.

One of the most important benefits of mass vaccination is the concept of herd immunity. In herd immunity, a large percentage of the population is resistant to a particular disease-causing agent. This indirectly protects people who are immunocompromised or otherwise unable to receive a vaccination for a particular communicable disease.

Another leading cause of hearing loss in young infants is cytomegalovirus infection, which rarely impacts healthy adults but can cross the placenta and cause disease in a growing fetus. As of this month, a number of messenger RNA vaccines are being developed by Moderna to prevent CMV infection.

Outbreaks of infectious diseases that can be controlled through the effective implementation of immunisation programs present a current threat to the wellbeing of vulnerable individuals. It is therefore of critical importance that people are made aware of how straightforward it can be to prevent the destruction that infectious diseases can inflict on the sensory organs.