B3 Fighting Disease - Vaccination (page 47) Flashcards
What do Vaccinations do?
it Protects us from future infections.
What happens when you’re infected with a new pathogen?
it takes your white blood cells a few days to learn how to deal with it. But by that time you can be pretty ill.
What do Vaccinations involve?
injecting small amounts of dead or inactive pathogens.
Why are dead or inactive pathogens injected into us for a vaccination?
The dead or inactive pathogens carry antigens, which cause your body to produce antibodies to attack them - even though the pathogen is harmless (since it’s dead or inactive).
What do the vaccine for MMR contain?
the MMR vaccine contains weakened versions of the viruses that cause measles, mumps and rubella (German Measles) all in one vaccine.
If after you’ve had a vaccine, and live pathogens of the same type appear, what can the white blood cells do?
they can rapidly mass-produce antibodies to kill off the pathogen.
(see diagram on page 47).
What are the ‘Pros of a Vacinnation?
1) Vaccines have helped control lots of communicable diseases that were once common in the UK (e.g. polio, measles, whopping couth, rubells, ups, tetanus….)
Smallpox no longer occurs at all, and polio infections have fallen by 99%
What are epidemics?
Big outbreaks of disease, they can be prevented if a large percentage of the population is vaccinated (such as covid).
That way, even the people who aren’t vaccinated are unlikely to catch the disease because there are fewer people able to pass it on, but if a significant number of people aren’t vacinnated, the disease can spread quickly through them and lots of people will be ill at the same time.
What are the Cons of vaccines?
1) Vaccines don’t always work - sometimes they don’t give you immunity.
2) You can sometimes have a bad reaction to a vaccine (e.g. swelling, or maybe something more serious like a feaver or seizures). But bad reactions are very rare.
Is prevention better than cure, and how can you decide this?
Yes.
Deciding whether to have a vaccination means balancing risks - the risk of catching the disease if you don’t have a vaccine, against the risk of having a bad reaction if you do. As always, you need to look at the evidence.
For example: if you get measles (the disease), there’s about a 1 in 15 chance that you’ll get complications (e.g. pneumonia) - and about 1 in 500 people who get measles actually die. However, the number who have a problem with the vaccine is more like 1 in 100,000.
Jane is vacinnated against Flu, and Paul isn’t. They are both exposed to a flu virus. Paul falls ill, whereas Jane doesn’t. Explain why? (2 marks)
Jane’s white blood cells recognise the antigens on the flu virus and rapidly produce antibodies which kill the pathogen (1 mark).
Paul’s white blood cells don’t recognise the antigens so it takes a while for them to produce antibodies and he becomes ill in the meantime (1 mark)
