Immunoglobulin (passive immunity)

Immunoglobulins like vaccination are used to prevent serious infections. An immune response to vaccination may take a  few days to a few weeks, whereas the action of immunoglobulin starts within a few hours of administration. On the contrary the immunity confers by the immunoglobulin lasts only a few months (up to 3 months), whereas that of the vaccine can be for decades or even for life. The immunoglobulins widely used at present are from pooled serum from previously infected individuals. There are a few number of  laboratory produced humanized monoclonal antibodies on use today, however they are very expensive.

Although most immunoglobulin is considered to be free from potentially pathogenic organism, there is still a theoretical risk of transmitting novel pathogens.  For this reason immunoglobulin should be used as the last resort to prevent infection.

 

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Human Normal Immunoglobulin is used to prevent infection with

1. Measles

The immunoglobulin can be used as prophylaxis after exposure to measles infection. It is effective if given within 72 hours.

It is recommended to be given for

Ø      Pregnant women

Ø      Immunocompromised patients

Ø      Infants under the age of 6 months

 

2. Hepatitis A

It is used as prophylaxis after exposure to hepatitis A virus. It should be given  between 7-14 days of exposure. If the patient present within the first week of exposure, vaccination with inactivated hepatitis A vaccine is effective to attenuate or prevent infection.

Currently in the UK, it is advised only after exposure to hepatitis A.

 

NB: all travelers traveling to hepatitis A virus endemic countries should be vaccinated (preferable 3 weeks before travel).

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RSV specific Immunoglobulin

Palivazumab

It is humanised monoclonal antibodies.

It should be given every month for 5 months during RSV seasons to prevent infection for children who have high risk of developing severe infection illnesses.

It is more expensive than the RespiGam.

It does not prevent infection from other respiratory virus.

 

RespiGam

This immunoglobulin is prepared from pooled plasma therefore it contains antibodies that neutralize a number of respiratory pathogens.

It is cheaper.

 

Indications

Ø      These immunoglobulins can be used after exposure or as prophylaxis in premature children during RSV seasons.

Ø      They can also be used to treat immunocompromised patients with RSV but they are not licensed for this purpose.

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Hepatitis B specific Immunoglobulin

It is used after exposure to hepatitis B virus.

 

Indication

Ø      After needle stick injury- the immunoglobulin is given only if the recipient is not already immune to hepatitis B virus infection.

Ø      For neonate after exposure to maternal blood if the mother is chronic carrier with high viral load or hepatitis B “e” antigen.

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Chickenpox specific Immunoglobulin

It is used as post-exposure prophylaxis to prevent or attenuate infections

Indications

Ø      To prevent infections in pregnant women after exposure to chickenpox or shingles.

Ø      To prevent infections in neonate after exposure to chickenpox or shingles if the mother does not have history of chickenpox or immunity.

Ø      To prevent infection in immunocompromised patient after exposure to chickenpox or shingles if she/he is considered to be susceptible.