Vaccinations

What are problems with live vaccines?

- Insufficient attenuation.

- Reversion to wild types.

- Foetal damage

What are problems with non-living vaccines?

- Contamination by toxins.

- Allergic reactions

- Autoimmunity

What are problems with genetically engineered vaccines?

Possible inclusion of oncogenes

What are the main types of vaccinations?

Passive and Active

Describe passive vaccinations.

- Patients are injected with antibodies or newborns recieve maternal immunoglobulin from mother's milk.

- Immune system is not activated.

- Provides immediate immunity however not long lasting (3months)

Describe active vaccinations.

- Patients are injected with antigens.

- Immune system is activated.

- Does not provide immediate immunity however lasts long (years-lifelong).

How is passive immunity used?

- To prevent disease after a known exposure.

- To protect immune deficient individuals.

- To block the action of bacterial toxins and prevent disease.

What are the types of active immunisation?

- Live vaccines

- Killed vaccines

Describe RNA vaccines

-mRNA is transported into cells which is programmed to to produce the antigens of a pathogen.

- This activates the immune system and starts an immune response providing immunity.

- The mRNA is held in a drug delivery vehicle to protect the strand.

What vaccines are infants provided at 2 months old?

Diphtheria, Tetanus, Whooping cough, Polio and Heamophilus influenza, menincoccoccus group b, Pneumococcal infection, rotavirus vaccine.

What vaccines are given to children?

What is the BCG vaccine?

- A TB vaccine that is prepared from a strain of attenuated live mycobacterium bovis.

- Only 70-80% effective against more severe forms of the disease and is less effective agaisnt the respiratory form of disease.

Describe the Mantoux test

Injection of PPD tuberculin into skin will cause a hard, red bump in patients with latent TB infections. Vaccine should not be provided if test is positive.

Describe the hepatitis b vaccine.

- Contains a killed part of hep B and is given in 3 doses.

- The babies of pregnant women who are carrying Hep B are given the vaccine at birth.

- People at risk of infection are offered the vaccine.

What is the vaccine schedule for people at risk of hep b?

- One injection the another after 4 weeks.

- Then again after 6 months.

- Booster after 10 years.

How is the hepatitis B vaccine administered to babies?

- First dose is given within 2 days of birth.

- A second dose is given at 1 month old

- A third at 2 months.

- A booster dose at 12 months old.

Describe the pneomoccal vaccine.

- Prevents against pneumococcal infection.

- People over 65 are offered the vaccine as well children at risk.

Describe the HPV vaccine

- Girls aged 12-13 are offered the vaccine to prevent cervical cancer.

- Also a three year catch up that will offer the HPV vaccine to 13-18 year old girls.

Describe the influenza virus.

- Provides 70-80% protection against infection.

- Found to reduce incidence of bronchopneumonia, hospital admissions and mortality.

- Produces some side effects of muscle aches and a high temperature.

What are the Salk and Sabin vaccines?

Two different types of vaccines for polio.

What are the differences between the Salk and Sabin vaccines?

- Salk is a killed vaccine whilst Sabin is an attenuated virus.

- Salk is administered intravenously whilst Sabin is orally so easier to consume and therefore people are more likely to stick to them.

- Sabin is more effective.

- Salk is safe for immune deficient individuals whilst Sabin is not.

- Sabin is cheaper than salk.

- Sabin can share immunity with other if they come in contact with unvaccinated

- Sabin moves into gut and therefore reduces spread of wild virus whereas salk is in the blood so wild type can spread more easily

- Sabin can cause polio whilst salk cannot

What are the similarities between the Salk and Sabin vaccines?

- Both stimulate production of antibodies.

- Both contribute to herd immunity

Is the measles vaccine live?

Yes, live and attenuated (active vaccination)

Is the rubella vaccine live?

Yes, live and attenuated (active vaccination)

How can attenuated vaccines be made?

Two main methods:

- Serial passage in cells cultured in vivo.

- Adaptation at low temperatures.

Describe serial passage in cells cultured in vivo when making attenuated vaccines.

- Virus is grown in a tissue culture e.g., monkey kidney cells.

- Every few days the virus is moved to different tissue cultures which leads to increased mutations.

- This produces an attenuated strain that can be tested in monkeys first then humans.

Describe how viruses can be killed.

- Different chemicals can be added.

- For example for viruses: Formaldehyde, Beta-propiolactone.

- For bacteria: Heat plus phenol or acetone is used or heat and formaldehyde.

- Colicin is also used to kill bacteria.