Vaccines Flashcards
Scientists have developed vaccines against HPV. One of the vaccines contains HPV antigens.What is an HPV antigen?
Protein / glycoprotein / glycolipid / polysaccharide; Causes immune response / antibody production;
A vaccine can be used to produce immunity to HPV. Describe how memory cells are important in this process.
Memory cells produced / remain / stored (from previous infection);(When individual) comes into contact with virus / antigen (again);Rapid / secondary / greater response / many or more antibodies produced;Destroys virus / antigen before it can cause harm / symptoms / cancer;
Some doctors suggested offering the vaccine to young men. Explain the advantage of vaccinating young men as well as young women.
HPV destroyed in males / prevents males being carriers of HPV;Prevents males passing on HPV (to unvaccinated females) / HPV may cause (other) cancers in males;
Immunity
the ability to be able to resist infection
passive immunity
antibodies have been given to you so the body does not have to make them. e.g. rabies antibody injection and tetanus antibody injection. antibodies from placenta and breast milk.- SHORT LIVED
active immunity
where your body responds to a pathogen and produces its own antibodies.
epidemic
when a disease effects a large number of people in a population and spread rapidly
pandemic
world wide spread of an infection.
herd immunity
where the majority of a population are immune to a pathogen it protects the few who are not
Most cases of cervical cancer are caused by infection with Human Papilloma Virus (HPV). This virus can be spread by sexual contact. There are many types of HPV, each identified by a number. Most of these types are harmless but types 16 and 18 are most likely to cause cervical cancer.A vaccine made from HPV types 16 and 18 is offered to girls aged 12 to 13. Three 5 injections of the vaccine are given over six months. In clinical trials, the vaccine has proved very effective in protecting against HPV types 16 and 18. However, it will be many years before it can be shown that this vaccination programme has reduced cases of cervical cancer. Until then, smear tests will continue to be offered to women, even if they have been vaccinated. A smear test allows abnormal cells in 10 the cervix to be identified so that they can be removed before cervical cancer develops.The Department of Health has estimated that 80% of girls aged 12 to 13 need to be vaccinated to achieve herd immunity to HPV types 16 and 18. Herd immunity is where enough people have been vaccinated to reduce significantly the spread of 15 HPV through the population.Use information from this passage and your own knowledge to answer the following questions.HPV vaccine is offered to girls aged 12 to 13 . Suggest why it is offered to this age group.
Girls are not sexually active / not likely to carry HPV vaccine may not work if already infected few girls sexually active (at this age)
The vaccine is made from HPV types 16 and 18 . Explain why this vaccine may not protect against other types of this virus
Other (HPV) types have different antigens;No memory cells for other types / memory cells not activated;Antibodies cannot attach to antigen / correct antibodies not produced / antibodies are not complementary
Three injections of the HPV vaccine are given . Use your knowledge of immunity to suggest why.
More antigen;More memory cells;So more antibodies produced / antibodies produced quicker (if infected)
It will be many years before it can be shown that the HPV vaccination programme has reduced cases of cervical cancer . Suggest two reasons why.
Cancer takes years to develop / develops later in life;Takes time for females to become sexually active / females must become sexually active to obtain data;Few people / only teenagers vaccinated
Smear tests will continue to be offered to women, even if they have been vaccinated . Suggest why women who have been vaccinated still need to be offered smear tests
(Cervical cancer) can be caused by other types of HPV / other factors / example given;OR(Some) women may have been infected (with HPV) before receiving the vaccine;OR(As a precaution) in case vaccine does not work / a way of monitoring if the vaccine has worked
Suggest one reason why vaccinating a large number of people would reduce significantly the spread of HPV through the population
Virus cannot replicate / is destroyed / is not carried (in vaccinated people)Non-vaccinated people more likely to contact vaccinated people
