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VACCINE PREVENTABLE DISEASES ADOLESCENTS AND ADULTS

GLOBAL IMMUNIZATION STRATEGIES

• Immunization programs increasingly including, in their national immunization schedules, vaccines that target age groups beyond infancy and early childhood

• One of the objectives of the Global Vaccine Action Plan (GVAP) is to extend the benefits of immunization to all children, adolescents and adults

• School-based immunization

• Due to increases in school enrollment rates, particularly in low-income countries, the school immunization strategy has become even more promising

• Outside agencies (CDC, WHO, UNICEF) assisting ministries of health in planning and managing immunization programs effectively

• Vaccine delivery coordinated with other preventive health care services for adolescents and adults

ADOLESCENTS

• Of the 7.2 billion people worldwide, over 3 billion are younger than 25 years,

• Make up 42% of the world population

• Approximately 1.2 billion of these young people are adolescents aged between 10 and

19 years

• Largely due to receiving vaccines as young children

• Vaccination of adult population not as successful

ADULTS AND VACCINATIONS

• Aging increases the risk and severity of infectious diseases

• Vaccination of adult population not as successful compared to children

• Improving the uptake rates of adult vaccination is essential to healthy aging

• The double threat of infectious diseases and NCDs continues to have an

impact globally in adults

• Resources rarely invested for this subpopulation

• Despite rising prevalence of these diseases

RAPID INCREASE IN GLOBAL POPULATION 60+ YEARS (1950 – 2015)

GLOBAL BURDEN OF KEY VACCINE PREVENTABLE CONDITIONS

IMMUNIZATIONS AND CANCER

• Every year, more than seven million people die from cancer worldwide

• Burden increasingly carried by developing countries

• Vaccines prevent infections that cause certain cancers such as liver and cervical

cancers

• One fifth of all cases of cancer are caused by infections like hepatitis B and

human papillomavirus (HPV)

• In the past decade, more than 3 million future deaths from liver cancer have

been prevented

IMMUNIZATIONS AND CANCER

• One in five cases of cancer is caused by infections like hepatitis B and human papillomavirus (HPV)

• Hepatitis B vaccine was the first vaccine developed to protect against a cancer

• Protects against the hepatitis B infection that causes an estimated 600,000 deaths from liver cancer.

• Cervical cancer is the number one cause of cancer deaths in adult women in low- income countries

• Kills 270,000 women each year, and over 80% of these deaths occur in the developing world

• HPV vaccines protect against human papillomaviruses types 16 and 18 which cause about 70% of cervical cancer cases

ADOLESCENT AND ADULT VACCINE PREVENTABLE DISEASES

HEPATITIS B

• Viral infection that attacks the liver and can cause both acute and chronic

disease

• Transmitted through contact with the blood or other body fluids of an infected

person

• Occupational hazard for health workers

• An estimated 296 million people were living with hepatitis B virus infection at

the end of 2019 with an estimated 1.5 new infections each year

• In 2019, hepatitis B resulted in 820,000 deaths, mostly from complications

HEPATITIS B VACCINE

• Vaccine against hepatitis B has been available since 1982.

• Is 95% effective in preventing infection and the development of chronic disease

and liver cancer due to hepatitis B

HEPATITIS B TRANSMISSION

• Virus can survive outside the body for at least 7 days.

• During this time, the virus can still cause infection if it enters the body of a person

who is not protected by the vaccine

• Incubation period is 75 days on average, but can vary from 30 to 180 days

• The virus may be detected within 30 to 60 days after infection and can persist

and develop into chronic hepatitis B

• In highly endemic areas, hepatitis B is most commonly spread from mother to

child at birth or through exposure to infected blood

HEPATITIS B TRANSMISSION

• Also spread by various body fluids, as well as through saliva, menstrual, vaginal, and seminal fluids

• Sexual transmission of hepatitis B may occur, particularly in unvaccinated men who have sex with men and heterosexual persons with multiple sex partners or contact with sex workers

• May also occur through reuse of needles and syringes either in health-care settings or among persons who inject drugs

• Infection can also occur during medical, surgical and dental procedures, through tattooing, or through the use of razors and similar objects that are contaminated with infected blood

HEPATITIS B SYMPTOMS

• Most people do not experience any symptoms during the acute infection phase

• However, some people have acute illness with symptoms that last several

weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme

fatigue, nausea, vomiting and abdominal pain

• A small subset of persons with acute hepatitis can develop acute liver failure,

which can lead to death

• In some people, the hepatitis B virus can also cause a chronic liver infection

that can later develop into cirrhosis or liver cancer

RISK FACTORS FOR CHRONIC DISEASE FROM HEPATITIS B

• The likelihood that infection becomes chronic depends upon the age at which a

person becomes infected.

• Children less than 6 years of age who become infected with the hepatitis B virus are the

most likely to develop chronic infections.

• 80–90% of infants infected during the first year of life develop chronic infections; and

30–50% of children infected before the age of 6 years develop chronic infections

• In adults, less than 5% of otherwise healthy persons who are infected as adults will develop

chronic infection; and

• 20–30% of adults who are chronically infected will develop cirrhosis and/or liver cancer

HEPATITIS B GEOGRAPHICAL DISTRIBUTION

• Prevalence is highest in the Western Pacific Region and the African Region,

where, respectively, 6.1% and 6.6% of the population is infected

• In the Eastern Mediterranean Region, the South-East Asia Region and the

European Region, an estimated 3.3%, 2.0% and 1.6% of the general population

is infected, respectively

• 0.7% of the population of the Region of the Americas is infected

HEPATITIS B VACCINE

• Recommended to be given at birth in most countries, usually within 24 hours

• Global coverage of birth dose for hepatitis B vaccine was 42%

• 3 doses, however, are required which provide protective antibody levels in more than

95% of infants, children and young adults

• All children and adolescents younger than 18 years-old and not previously

vaccinated should receive the vaccine if living in countries where there is low

or intermediate endemicity

HIGH RISK GROUPS

• In these settings more people in high-risk groups may acquire the infection:

• People who frequently require blood or blood products, dialysis patients, recipients of solid organ transplantations

• People interned in prisons

• Persons who inject drugs

• Household and sexual contacts of people with chronic HBV infection

• People with multiple sexual partners

• Healthcare workers and others who may be exposed to blood and blood products through their work

• Person who have not completed their hepatitis B vaccination series and are travelling to endemic areas

HUMAN PAPILLOMAVIRUS (HPV)

• Group of viruses that are extremely common worldwide

• More than 100 types of HPV, of which at least 14 are cancer-causing

• Primarily transmitted through sexual contact

• Two HPV types (16 and 18) cause 70% of cervical cancers and pre-cancerous cervical lesions

• Non-cancer causing types of HPV (especially types 6 and 11) can cause genital warts and respiratory papillomatosis (a disease in which tumors grow in the air passages leading from the nose and mouth into the lungs)

• Rarely result in death but may cause significant occurrence of disease

• Genital warts are very common, highly infectious, and affect sexual life

CERVICAL CANCER

• Cervical cancer is the second most common cancer in women living in less developed regions with an estimated 604,000 new cases in 2020

• Approximately 90% of all new cervical cancer cases occurred in low- and middle-income countries

• Cervical cancer is by far the most common HPV-related disease. Nearly all cases of cervical cancer can be attributable to HPV infection.

• In 2020, approximately 342,000 women died from cervical cancer

• 90% of these deaths occurred in low- and middle-income countries

• Takes 15 to 20 years for cervical cancer to develop in women with normal immune systems

• Can take only 5 to 10 years in women with weakened immune systems, such as those with untreated HIV infection

CERVICAL CANCER CONTROL

• Comprehensive approach to cervical cancer prevention and control

• Includes interventions across the life course

• Should be multidisciplinary, including components from community education,

social mobilization, vaccination, screening, treatment and palliative care

• Begins with HPV vaccination of girls aged 9-14 years, before they become

sexually active

• Education about safe sexual practices

• Promotion and provision of condoms

CERVICAL CANCER CONTROL

• Sexually active women screened for abnormal cervical cells and pre-cancerous

lesions, starting at 30 years of age

• If treatment of pre-cancer is needed, cryotherapy is recommended

• If signs of cervical cancer are present, treatment options for invasive cancer

include surgery, radiotherapy, and chemotherapy

MENINGOCOCCAL MENINGITIS

• Bacterial form of meningitis, a serious infection of the thin lining that surrounds

the brain and spinal cord

• High fatality rates (up to 50% when untreated) and can cause severe brain

damage

• Early antibiotic treatment is the most important measure to save lives and reduce

complications

• The disease can affect anyone of any age, but mainly affects babies, preschool

children, adolescents, and young adults

MENINGOCOCCAL MENINGITIS

• Twelve types of N. meningitides, called serogroups, have been identified, six of

which (A, B, C, W, X and Y) can cause epidemics

• Geographic distribution and epidemic potential differ according to the

serogroup

• No reliable estimates of global meningococcal disease burden due to

inadequate surveillance in several parts of the world

• The largest burden of meningococcal disease occurs in an area of sub-Saharan

Africa known as the meningitis belt, which stretches from Senegal in the west

to Ethiopia in the east (26 countries)

MENINGOCOCCAL MENINGITIS

• During the dry season between December to June, dust winds, cold nights and

upper respiratory tract infections combine to damage the nasopharyngeal

mucosa, increasing the risk of meningococcal disease

• Transmission of N. meningitidis may be facilitated by overcrowded housing

• This combination of factors explains the large epidemics which occur during the dry

season in the meningitis belt (Sub-Saharan Africa)

• Stretches from Senegal in the west to Ethiopia in the east (26 countries)

MENINGOCOCCAL MENINGITIS: TRANSMISSION

• Transmitted from person-to-person through droplets of respiratory or throat

secretions from carriers

• Smoking, close and prolonged contact facilitates the spread of the disease.

• The bacteria can be carried in the throat and sometimes overwhelms the

body's defenses allowing the bacteria to spread through the bloodstream to

the brain

• Believed that 1% to 10% of the population carries N. meningitidis in their throat

at any given time.

• Carriage rate may be higher (10% to 25%) during epidemics

MENINGOCOCCAL MENINGITIS: SYMPTOMS

• Average incubation period is four days, but can range between two and 10 days

• Common symptoms - stiff neck, high fever, sensitivity to light, confusion, headaches

and vomiting

• Less common but even more severe (often fatal) form is meningococcal septicemia,

• Characterized by a hemorrhagic rash and rapid circulatory collapse

• Even when the disease is diagnosed early and adequate treatment is started, 8% to

15% of patients die, often within 24 to 48 hours after the onset of symptoms

• If untreated, meningococcal meningitis is fatal in 50% of cases and may result in

brain damage, hearing loss or disability in 10% to 20% of survivors

PREVENTION: VACCINATION

• Licensed vaccines against meningococcal disease have been available for more than 40 years

• No universal vaccine against meningococcal disease exists

• Vaccines are serogroup specific and confer varying degrees of duration of protection

• Types of vaccines available

• Vaccines used during a response to outbreaks, mainly in Africa

• Vaccines are used in routine immunization schedules and preventive campaigns and outbreak response

• Recommended during adolescence

PREVENTION: CHEMOPROPHYLAXIS

• Antibiotic prophylaxis for close contacts, when given promptly, decreases the

risk of transmission

• Outside the African meningitis belt, chemoprophylaxis is recommended for

close contacts within the household

• In the meningitis belt, chemoprophylaxis for close contacts is recommended in

non-epidemic situations

GLOBAL PUBLIC HEALTH RESPONSE – RECENT MENINGOCOCCAL A CONJUGATE

VACCINE INTRODUCTION SUCCESS IN AFRICA

• Meningitis epidemics in the African meningitis belt constitute an enormous public health burden.

• In December 2010, a new meningococcal A conjugate vaccine was introduced in Africa through mass campaigns targeting persons 1 to 29 years of age.

• As of November 2017, more than 280 million persons have been vaccinated in 21 African belt countries.

• Considered safe and is cheap

• Associated with a 58% decline in meningitis incidence and 60% decline in the risk of epidemics

• Can be given as soon as 1 year of age, thus it has now been introduced into routine infant immunization

INFLUENZA

• Circulate throughout the world

• 4 types of seasonal influenza viruses, types A-D

• Influenza A and B viruses circulate and cause seasonal epidemics of disease

• Characterized by a sudden onset of fever, cough, headache, muscle and joint pain, severe malaise, sore throat and a runny nose. The cough can be severe and can last 2 or more weeks

• Most people recover from fever and other symptoms within a week without requiring medical attention.

• Can cause severe illness or death especially in people at high risk.

INFLUENZA

• Hospitalization and death among high risk groups.

• Worldwide, annual epidemics are estimated to result in about 3 to 5 million cases of severe illness, and about 290,000 to 650,000 respiratory deaths

• In industrialized countries most deaths associated with influenza occur among people age 65 or older

• Epidemics can result in high levels of worker/school absenteeism and productivity losses. Clinics and hospitals can be overwhelmed during peak illness periods

• Effects of seasonal influenza epidemics in developing countries are not fully known

• Research estimates that 99% of deaths in children under 5 years of age with influenza related lower respiratory tract infections are found in developing countries

HIGH RISK GROUPS

• People at greater risk of severe disease or complications when infected are:

• Pregnant women

• Children under 59 months

• Elderly individuals

• Individuals with chronic medical conditions

• Individuals with immunosuppressive conditions

• Health care workers are at high risk to acquire influenza

TRANSMISSION

• Seasonal influenza spreads easily

• Rapid transmission in crowded areas including schools and nursing homes

• When an infected person coughs or sneezes, droplets containing viruses (infectious

droplets) are dispersed into the air and can infect persons in close proximity

• Can also be spread by hands contaminated with influenza viruses.

• In temperate climates, seasonal epidemics occur mainly during winter, while in

tropical regions, influenza may occur throughout the year, causing outbreaks more

irregularly

• Incubation period - 2 days, but ranges from one to four days

INFLUENZA AND VACCINATION

• The most effective way to prevent the disease is vaccination.

• Safe and effective vaccines used for more than 60 years

• Immunity from vaccination wanes over time so annual vaccination is

recommended to protect against influenza

• Vaccination is especially important for people at high risk of influenza

complications, and for people who live with or care for the people at high risk

INFLUENZA AND VACCINATION

• Annual vaccination recommended for:

• Pregnant women at any stage of pregnancy

• Children aged between 6 months to 5 years

• Elderly individuals (aged more than 65 years)

• Individuals with chronic medical conditions

• Health-care workers

• In the US, the strains that the influenza vaccine protects against may change

from year to year

INFLUENZA PERSONAL PROTECTIVE MEASURES

• Apart from vaccination personal protective measures are also recommended

• Regular hand washing

• Good respiratory hygiene

• Early self-isolation of those feeling unwell, feverish, and having other symptoms of

influenza

• Avoiding close contact with sick people

• Avoiding touching one’s eyes, nose or mouth

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