Vaccines W8

Question 1

Aims of vaccination

Answer 1

aims vary from blocking transmission and preventing symptoms to eradication of disease

• smallpox has been eradicated using vaccination
• polio can also be eradicated,
• in certain cases aim of vaccination will be much more limited:
• protect individuals against symptoms or pathology

Question 2

problems with vaccine safety

Answer 2

live attenuated vaccines:
- insufficient attenuation
- administration to immunodeficient patient
- contamination by other viruses
- foetal damage

non-living vaccines:
- contamination by toxins
- allergic reactions
- autoimmunity

genetically engineered vaccines:
- possible inclusion of oncogenes

Question 3

passive immunization

Answer 3

injection of purified antibody or antibody-containing serum to provide rapid, temporary protection or treatment of a person is termed passive immunization

Newborns receive natural passive immunity from maternal immunoglobulin that crosses the placenta or is present in the mother’s milk

Question 4

active immunization

Answer 4

stimulates the body’s immune system to produce a response against a specific pathogen, providing long-term immunity.
This is achieved by exposing the immune system to a harmless form or part of the pathogen, allowing it to “learn” how to recognize and fight the actual disease-causing organism if encountered in the future.

Question 5

Living versus nonliving vaccines (composition, example, immune response, benefits, limitations)

Answer 5

Composition:
-Living contain a weekend form of the pathogen that is still alive but unable to cause disease
- Nonliving contain an inactivated pathogen

Example:
-Living = MMR vaccine
- Nonliving hepatitis B vaccine

Immune response :
-Living Mimics a natural infection producing a long lasting immune response
-Nonliving does not mimic natural infection but triggers a robust antibody mediated response

Benefits :
- Living often requires fewer doses or boosters
-Nonliving no risk of infection or disease and safer for immunocompromised individuals

Limitations:
-Living cannot be given to immunocompromised, requires strict storage and risk of reversion to a virulent form
-Nonliving may require multiple doses or boosters and cellular immunity is often weaker compared to live vaccines

Question 6

DNA vaccinations

Answer 6

Intramuscular injection of DNA with a suitable promoter can immunise laboratory animals against infection such as influenza and malaria

Much work is still needed to verify how it works and if it can be used as a vaccine

Question 7

RNA vaccine

Answer 7

New type of vaccine insert fragments of viral mRNA into human cells which are reprogrammed to produce pathogen antigens which then stimulates an adaptive immune response against the pathogen

Question 8

COVID-19 vaccine

Answer 8

Was co-invented by the University of Oxford and it uses a replication deficient chimpanzee viral vector based on the weak version of a common cold virus

95% effective against COVID-19 beginning after 28 days of the first dose

Question 9

Factors affecting global eradication of an infectious disease

Answer 9

Disease is limited to humans - no reinvasion by microbe from animal host

No long-term career status - no reinvasion by microbe from human carriers

Cases easily recognised clinically
One or few serotypes
Stable, cheap, effective
Eradication program is cost-effective

Question 10

Routine childhood immunisations by age

Answer 10

Two months old - diphtheria, tetanus polio, hib

Three months old - Syria tetanus, polio, meningitisC, rotavirus, hib

Four months old - diphtheria, tetanus polio, hib, pneumococcal, meningitis B

12 months - hib, meningitisC

13 months - MMR, pneumococcal, meningitisB

2 to 6 years - flu

Three years - diphtheria tetanus polio measles mumps rubella

12 to 13 years - cervical cancer

13 to 18 years - diphtheria tetanus polio

13 to 15 years - meningitisC booster

Question 11

Non-routine immunisations

Answer 11

At birth, tuberculosis (babies who are more likely to come in contact with TB then the general population) and hepatitis B (to babies whose mothers are hepatitis B positive)

Question 12

BCG

Answer 12

Bacillus of Calmette and Guérin (BCG) is a vaccine against tuberculosis that is prepared from a strain of the attenuated (weakened) live bovine tuberculosis bacillus, Mycobacterium bovis

it has lost its virulence in humans by specially culturing in artificial medium for years

Question 13

BCG recommendation

Answer 13

All children in areas where the incidents of TB is 40/100,000 or greater

Previously unvaccinated immigrants from countries with high TB incidents

Question 14

Mantoux test for TB

Answer 14

Involves intradermally injecting PPD tuberculin and measuring the size of induration 48 to 72 hours later

Should be done before immunisation as positive test they should not be vaccinated

If test is strongly positive, patient must undergo further investigations to check if they have TB

Question 15

Hepatitis B vaccine

Answer 15

The vaccine contains a killed part of the hepatitis B virus and is given in three doses

All pregnant women are offered a screening for hepatitis B and if found to be carriers during pregnancy their babies are given the vaccine at the start of birth

Schedule :
- 1st injection
- After four weeks, 2nd injection
- after six months, 3rd injection
- Boost after 10 years

Question 16

Schedule of hepatitis B vaccine given to all babies whose mother are close family have been infected with hepatitis B

Answer 16

First dose at two days of birth

Second dose at one month

Third dose of two months

Booster dose and blood test at 12 months

Question 17

Effectivity and length of protection of hepatitis B vaccine as well as side-effects

Answer 17

Effective for the majority of babies, children and young adults but people over 40 are slightly less likely to become immune to hepatitis B after course of the vaccine

We don’t know yet how long the vaccine protects people as it was only introduced in the 1980s however the evidence so far suggest people that develop immunity vaccination stay immune for life

The most common side effects are temporary pain at the injection site and a slight fever

Question 18

pneumococcus

Answer 18

The pneumococcal vaccine protects against pneumococcal infection

The infection can cause diseases such as pneumonia, septicaemia and meningitis

Older people are more at risk

People over 65 and our routine offered a vaccine

It was the childhood immunisation program in 2006

Question 19

Cervical cancer

Answer 19

Since September 2008 there has been a national program to vaccinate girls age 12 to 13 against HPV

There are more than 100 different types of HPV virus with about 40 affecting the genital area

In the UK7 cancer is the 12th most common women’s cancer

Question 20

MMR and autism

Answer 20

There is no proof that MMR causes the development of autism

The age that children develop autism is the same age that the vaccine is given