Table. Appropriate evidence of long-term immunity against vaccine-preventable diseases

• Documentation of an appropriate vaccination course, including booster doses where necessary

• Prior infection does not induce lasting immunity
• No validated correlate of protection available

• Documentation of age- and risk-category appropriate vaccination course.

• Prior infection does not induce lasting immunity  
• A correlate of protection is not clearly established, but a threshold level of ≥0.01 IU/mL (minimum level required for protection) or ≥1.0 IU/mL (for long-term protection) are considered protective. Exact values indicating a positive result vary depending on the commercial assay used.

• Documentation of age-appropriate vaccination given within the recommended timeframe, including booster doses.

• Prior infection does not induce lasting immunity
• Serological testing can be used by specialist clinicians to assess response to vaccination in people suspected to have an inborn error of immunity
• Correlate of protection: 0.01–0.1 IU/mL diphtheria toxin neutralising antibody

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.

• Prior infection does not induce lasting immunity
• Serological testing can be used by specialist clinicians to assess response to vaccination in people suspected to have an inborn error of immunity
• Correlate of protection: 0.15 µg/mL anti-PRP ELISA antibodies

• Documentation of 2 doses of hepatitis A vaccination, OR
• Serological evidence of prior infection. See hepatitis A serological testing recommendation for details.

• Previous infection with hepatitis A usually results in lifelong immunity. However, this should be confirmed by serological testing.
• People with likely or confirmed prior infection can still be vaccinated safely if they prefer not to undergo serological testing
• Correlate of protection: 20 mIU/mL ELISA antibodies

• Documentation of a complete age- and risk-appropriate course of vaccination is adequate evidence for healthy people who are not in a risk group.
• Certain people at risk of hepatitis B also require serological evidence of immunity (ie hepatitis B surface antibody (anti-HBs) ≥10 mIU/mL). See recommendation: people at risk of hepatitis B are recommended to have serological testing 4-8 weeks after they complete the hepatitis B vaccination course.  
• Serological evidence of prior infection or vaccination is acceptable evidence of long-term immunity

• Previous and chronic infection with hepatitis B usually results in lifelong immunity. This can be confirmed by serological testing.  
• Vaccination is not recommended after prior natural infection
• Correlate of protection: anti-HBs titre ≥10 IU/L

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.  

• Prior infection does not induce lasting immunity; additionally, immunity against one HPV genotype does not confer immunity against other HPV genotypes.
• No validated correlate of protection published

• Documentation of annual influenza vaccination.

• Prior infection does not induce lasting immunity; additionally, the influenza virus evolves over time, and immunity in one year does not necessarily confer immunity against future seasonal circulating influenza viruses.
• No validated correlate of protection available; haemagglutination inhibition antibody titre of 32 to 40 is often used but does not guarantee protection

• Documentation of age- and risk-appropriate vaccination, including booster doses where necessary.

• While a correlate of protection exists, serological testing to assess responses to vaccination is not routinely available.
• Correlate of protection: JEV PRNT 50 titre of ≥1:10

For people born during or since 1966:

• Documentation of 2 doses of measles-containing vaccine (ie MMR or MMRV) given at least 4 weeks apart, OR
• Serological evidence of immunity to measles, OR
• Documented history of laboratory-confirmed measles infection.

People born before 1966 are considered immune, and do not require vaccination or serological testing.  

• Fully vaccinated people (ie people who have received age-appropriate vaccination with 2 doses of vaccine given at least 4 weeks apart) without a severely immunocompromising condition who receive a negative serological test result can be considered protected against disease. Negative serological test results are typically due to limitations with current available serological tests.
• People born before 1966 are considered immune due to prior (natural) exposure to the virus, but can still safely receive vaccine
• Correlate of protection: ≥120 mIU/mL ELISA measles antibodies

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe (for both MenACWY and MenB vaccines).

• Prior infection does not induce immunity against other serogroups  
• While a correlate of protection exists, serological testing to assess responses to vaccination is challenging to conduct and interpret so is not routinely recommended.
• Correlates of protection vary by serogroup and are not perfect predictors of protection: ≥1/4 hSBA for serogroup B; ≥1/4 hSBA or ≥1/8 rSBA for serogroups A, C, W and Y

• Documentation of an appropriate vaccination course, including booster doses where necessary.

• No validated correlate of protection available

For people born during or since 1966:

• Documentation of 2 doses of mumps-containing vaccine (ie MMR or MMRV) given at least 4 weeks apart, OR
• Serological evidence of immunity to mumps, OR
• Documented history of laboratory-confirmed mumps infection.

People born before 1966 are considered immune, and do not require vaccination or serological testing.  

• Fully vaccinated people (ie people who have received age-appropriate vaccination with 2 doses of vaccine given at least 4 weeks apart) without a severely immunocompromising condition who receive a negative serological test result can be considered fully protected – negative results are typically due to limitations with current serological tests
• People born before 1966 are considered immune, but can still safely receive vaccine  
• Correlates of protection for mumps are not well-defined

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe, including booster doses.

• Prior infection does not induce lasting immunity
• No validated correlate of protection available

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.

• Prior infection does not induce lasting immunity against other serotypes
• Serological testing can be used by specialist clinicians to assess response to vaccination in people suspected to have an inborn error of immunity
• Correlate of protection: 0.20–0.35 µg/mL ELISA antibodies is widely accepted, but best applied to the population level rather than individuals

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.

• Prior infection does not induce lasting immunity against other serotypes
• While a correlate of protection exists, serological testing to assess response to vaccination is not routinely available.
• Correlate of protection: ≥1/8 neutralising antibodies 

• Documentation of previous Q fever vaccination, OR
• Documented history of previous infection with Q fever, OR
• Serological evidence of immunity to Q fever, confirmed with a serum antibody test and a skin test (which should be completed if a person is being considered for Q fever vaccination)

• People who are being considered for Q fever vaccination must have both serum antibody testing and a skin test before Q fever vaccination
• People who have been previously infected with the Q fever organism should not be vaccinated
• Serological testing is not required if either of the other criteria (documented history of Q fever infection or documented Q fever vaccination) are met 

• Documentation of an appropriate course of rabies vaccination
• People with ongoing occupational exposure risk should have serological testing to confirm immunity, and receive booster doses as necessary
• Some people additionally require serological testing to confirm immunity following vaccination, including people who receive pre-exposure prophylaxis by the intradermal route and immunocompromised people

• The dose schedule for rabies vaccination varies for pre- and post-exposure prophylaxis. See the rabies and other lyssaviruses chapter for details on vaccination recommendations and when serological testing is required.
• Correlate of protection: rabies virus neutralising antibody (VNab) titre ≥0.5 IU per mL or equivalent antibody titre measured by ELISA assay

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.

• Prior infection does not induce lasting immunity
• No validated correlate of protection available

• Documentation of age-appropriate vaccination given within the recommended timeframe.

• Only children aged <6 months are eligible for vaccination
• Prior infection does not induce lasting immunity
• No validated correlate of protection available 

For people born during or since 1966:

• Documentation of 2 doses of rubella-containing vaccine (ie MMR or MMRV) given at least 4 weeks apart, OR
• Serological evidence of immunity to rubella, OR
• Documented history of laboratory-confirmed rubella infection.

People born before 1966 are considered immune, and do not require vaccination or serological testing.  

• Pregnant women and women planning pregnancy are required to undergo screening to confirm immunity against rubella during each pregnancy, even if they have documented evidence of complete vaccination  
• Fully vaccinated people (ie people who have received age-appropriate vaccination with 2 doses of vaccine given at least 4 weeks apart) without a severely immunocompromising condition who receive a negative serological test result can be considered fully protected – negative results are typically due to limitations with current serological tests
• People born before 1966 are considered immune, but can still safely receive vaccine  
• Correlate of protection: ≥10–15 IU/mL ELISA rubella antibodies 

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.

• Prior infection does not induce lasting immunity
• Serological testing can be used by specialist clinicians to assess response to vaccination in people suspected to have an inborn error of immunity  
• Correlate of protection: 0.01–0.1 IU/mL tetanus toxin neutralising antibody

• Documentation of BCG vaccination

• The need for a tuberculin skin test (TST) before BCG vaccination is only recommended in certain circumstances, based on risk factors for previous tuberculosis exposure, and is used to determine prior exposure to M. tuberculosis or latent infection; see the complete recommendation
• No validated immunological correlate of protection available

• Documentation of an appropriate vaccination course, including booster doses where necessary.

• No validated correlate of protection available

• Documentation of 2 doses of varicella-containing vaccine given at least 4 weeks apart, OR
• Serological evidence of immunity, see recommendation Serological testing for varicella immunity from infection or vaccination, OR
• Documented history of varicella infection

• Currently available assays do not reliably detect antibodies post-immunisation. A negative test result in a fully vaccinated person (ie people who have received age-appropriate vaccination with 2 doses of vaccine given at least 4 weeks apart) should be interpreted with caution.
• People who have been exposed to varicella infection may undergo serological testing to determine immunity. See recommendations for public health management in the Varicella chapter.
• If there is not a confident clinical diagnosis of previous infection, the person should receive varicella vaccine.
• Correlate of protection: ≥5 U per mL IgG antibodies to VZV

• Documentation of vaccination with 1 dose of yellow fever vaccine
• For people who require a booster dose, either documented vaccination or serological evidence of immunity is acceptable.

• A single dose of yellow fever vaccination provides life-long protection in most people
• Booster doses are only required in very rare circumstances (eg people who were pregnant or who had HIV when they received their first dose)
• Correlate of protection: ≥0.7 LNI neutralising antibodies 

• Documentation of age- and risk-appropriate vaccination given within the recommended timeframe.

• Prior episode(s) does not provide protection against future episodes

Acronyms used:

• Anti-HBs: hepatitis B surface antibody;
• BCG: Bacille Calmette-Guérin;
• Hib: Haemophilus influenzae B;
• HPV: human papillomavirus;
• hSBA: human serum bactericidal antibody;
• JEV PRNT: Japanese encephalitis virus plaque reduction neutralisation test;
• LNI: log10 neutralization index;
• MenACWY: meningococcal ACWY;
• MenB: meningococcal B;
• MMR: measles-mumps-rubella;
• MMRV: measles-mumps-rubella-varicella;
• PRP: polyribosylribitol phosphate;
• rSBA: rabbit serum bactericidal antibody;
• RSV: Respiratory Syncytial Virus;
• TST: tuberculin skin test;
• VNab: virus neutralising antibody;
• VZV: varicella-zoster virus