Vaccination is the administration of a vaccine to help the immune system develop protection from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism. In stimulating the body’s adaptive immunity, they help prevent sickness from an infectious disease.
When a sufficiently large percentage of a population has been vaccinated and become immune, herd immunity results which indirectly protects the non-immune population because infection transmission is low. The effectiveness of vaccination has been widely studied and verified. Vaccination is a most effective method of preventing infectious diseases.
Vaccination and immunization have a similar meaning in everyday language. This is distinct from inoculation, which uses unweakened live pathogens.
Germs can be viruses (such as the measles virus) or bacteria (such as pneumococcus). Vaccines stimulate the immune system to react as if there were a real infection. It fends off the “infection” and remembers the germ. Then, it can fight the germ if it enters the body later.
There are 4 main types of vaccines: Live-attenuated vaccines, recombinant, polysaccharide, and conjugate vaccines
Antibodies are specific to each individual disease. Having antibodies to measles does not protect you from catching mumps or chicken-pox, etc.
Active and passive Immunization
Active immunization: this happens by being exposed to a disease causing organism, either by catching it in the normal way or through vaccination with a dose of the responsible virus or bacteria which has been killed or inactivated. This is usually long lasting. It may take some time to fully develop and often needs ‘boosting’.
Passive immunization: this is a way of giving immediate immunity by injecting already existing antibodies (from someone else) into a person who has just been, or may shortly be, exposed to a particular infection. Passive immunity is immediately effective, but doesn’t last for long.
Childhood immunization: The creation of immunity through vaccination is usually started at birth. Different countries have different immunization schedules based on global and national prevalence.
Adult immunization: As well as being of vital importance in childhood, vaccination is also essential for adults. Some are boosters from childhood vaccines while others are travel vaccines required when going to a country with different infection prevalence.
The term ‘hepatitis‘ means inflammation of the liver. Hepatitis can be caused by viruses, other infectious agents, alcohol, and other chemicals. There are various Hepatitis viruses which include A, B, C, D, E and possibly G. Types A, B and C are the most common. All can cause acute hepatitis. Viral Hepatitis B and C can cause Chronic Hepatitis which can lead to Liver Cirrhosis (fibrosis) and in some cases Liver cancer (Hepatocellular carcinoma). They differ in the way they are transmitted from person to person.
Hepatitis B vaccine
Hepatitis B is caused by hepatitis B virus (HBV), and is spread by contact with body fluids, such as blood( blood transfusion with infected blood products), saliva, semen, or vaginal fluids (sexual intercourse); by needle sticks or sharing needles; or from mother to child. Inadvertent exposure to infected blood or body fluids may occur during tattooing, body piercing, or when sharing razors or toothbrushes with an infected person. Persons infected with hepatitis B may be asymptomatic or may develop fatigue, jaundice, and weight loss, liver failure and possible death.
Most infected adults are able to clear the hepatitis B virus from their body and become immune to further infections with hepatitis B. However, some people are not able to clear the hepatitis B virus and it progresses to chronic (persistent) infection and inflammation of the liver. Most infants infected at birth and 25% to 50% of infected children aged 1–5 years have chronic persistent infection.
Chronic infection may be mild or may damage the liver.
Vaccination has reduced the number of new cases of hepatitis B by more than 75% in the United States. The hepatitis B vaccine contains a protein (antigen) that stimulates the body to make protective antibodies. Hepatitis B vaccines are effective and safe.
Centers that serve high-risk individuals are encouraged to provide the vaccine to their clients. Such centers include: dialysis units, drug treatment facilities, sexually transmitted diseases clinics and correctional facilities.
A blood test for hepatitis B antibodies is recommended after vaccination to ensure that antibodies have been produced. For the few who do not form antibodies, revaccination may improve the response, especially in infants. However, a small proportion of individuals will never respond to hepatitis B vaccination. Side effects from the vaccine usually are mild, primarily soreness at the site of injection. The risk of serious allergic reactions (anaphylaxis) is less than one per million doses.
In the United States, hepatitis B vaccination is recommended for all infants at birth. Older children and adolescents should receive the vaccine if they did not receive it at birth. Adults in high risk situations also are advised to receive hepatitis B vaccine.
Some countries have a high prevalence of hepatitis B in their population. Travelers who visit these countries for a prolonged period of time (usually 6 months or longer) and those who may be exposed to blood or semen should consider vaccination.
Unvaccinated individuals who are exposed to a known case of hepatitis B or to a person at high risk for hepatitis B should be evaluated by a physician. Examples of such exposures include needle stick injuries in health care workers or sexual intercourse with an infected person. If the exposure is significant, the physician will recommend vaccination and may also recommend an injection of hepatitis B immune globulin (HBIG). HBIG is prepared from the plasma of blood donors and contains antibodies to hepatitis B. Vaccination and HBIG can substantially reduce the risk of disease in persons exposed to hepatitis B if given within one week of a needle stick or two weeks of sexual intercourse.
The major cause of liver cancer is hepatitis B and C, and can develop silently as the liver becomes cirrhotic. Blood tests, ultrasound examinations, CT and MRI scans can identify the cancers (seen here in green). Biopsy of the liver is needed to definitely make a diagnosis of cancer. If the cancers are found early, a small proportion of patients can be cured.
Human papillomavirus (HPV)
Human papillomavirus (HPV) is a viral infection that is passed between people through skin-to-skin contact. There are over 100 varieties which are passed through sexual contact and can affect your genitals, mouth, or throat. Most people get a genital HPV infection through direct sexual contact, including vaginal, anal, and oral sex.
Because HPV is a skin-to-skin infection, intercourse isn’t always required for transmission to occur.
Many people have HPV and don’t even know it, which means you can still contract it even if your partner doesn’t have any symptoms. It’s also possible to have multiple types of HPV.
In rare cases, a mother who has HPV can transmit the virus to her baby during delivery. When this happens, the child may develop a condition called recurrent respiratory papillomatosis where they develop HPV-related warts inside their throat or airways.
HPV in men
Many men that are infected with HPV have no symptoms, although some may develop genital warts. See your doctor if you notice any unusual bumps or lesions on your penis, scrotum, or anus.
Some strains of HPV can cause penile, anal, and throat cancer in men. Some men may be more at risk for developing HPV-related cancers, including men who receive anal sex and men with a weakened immune system.
The strains of HPV that cause genital warts aren’t the same as those that cause cancer. Get more information about HPV infection in men.
HPV in women
It’s estimated that 80% of women will contract at least one type of HPV during their lifetime. Like with men, many women that get HPV don’t have any symptoms and the infection goes away without causing any health problems.
Some women may notice that they have genital warts, which can appear inside the vagina, in or around the anus, and on the cervix or vulva.
Make an appointment with your doctor if you notice any unexplained bumps or growths in or around your genital area.
Some strains of HPV can cause cervical cancer or cancers of the vagina, anus, or throat. Regular screening can help detect the changes associated with cervical cancer in women. Additionally, DNA tests on cervical cells can detect strains of HPV associated with genital cancers.
The HPV vaccine helps protect you against certain types of HPV that can lead to cancer or genital warts.
HPV types 16 and 18 — the 2 types that cause 80% of cervical cancer cases.
HPV types 6 and 11, which cause 90% of genital warts cases.
Others (types 31, 33, 45, 52, and 58) that can lead to cancer of the cervix, anus, vulva/vagina, penis, or throat
The HPV vaccine is given in a series of shots. For people ages 15-45, the HPV vaccine is 3 separate shots 0, 1 month and 6 months. So, in all, it takes about 6 months to get all 3 shots.
For people ages 9-14, you only need to get 2 shots. The second shot is given 6 months after the first shot.
The HPV vaccine is routinely recommended for girls and boys ages 11 or 12, although it can be given as early as age 9. It’s ideal for girls and boys to receive the vaccine before they have sexual contact and are exposed to HPV.