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24 May 2022

Document 1
Memo 
COVID-19  Vaccine  Technical  Advisory  Group  (CV  TAG)  recommendations:  
Vaccination after infection with SARS-CoV-2 
Date: 
22 March 2022 
To: 
Dr Ashley Bloomfield, Director-General of Health 
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Cc: 
Astrid Koornneef, Director, National Immunisation Programme 
Maree Roberts, DDG, System Strategy and Policy 
ACT 
Dr Caroline McElnay, Director of Public Health 
From: 
Dr Ian Town, Chief Science Advisor 
For your: 
Consideration
INFORMATION 
Purpose of report 
1.
To summarise the COVID-19 Vaccine Technical Advisory Group’s (CV TAG) recommendations
on COVID-19 vaccination after infection in circumstances when the recommended course of
vaccination has not been completed. OFFICIAL 
Background 
THE 
2.
COVID-19 is an acute viral infection caused by the SARS-CoV-2 virus, which provokes
antibody and cellular immune responses.
3.
Studies using samples from previously infected (but not vaccinated) people have shown that
the level of detectable antibodie
UNDER  s varies among individuals. [1-4] However, most of these
studies were performed before the emergence of the Delta or Omicron variants, and thus rely
on data about infection with earlier variants.
4.
The proportion of people with detectable antibody might vary depending on whether
infections are symptomatic. In one study, 81% of (symptomatic) COVID-19 outpatients had
detectable antibodies after infection. However, this value was only 15% in asymptomatic
RELEASED 
patients, suggesting that the majority of asymptomatic patients could be susceptible to early
re-infection. [4] Other studies have shown that more than 90% of infected individuals have
antibody and cellular responses lasting up to 8 months. [1] However, to date, no studies have
investigated responses longer than 8 months.
5.
The protection gained from infection prior to vaccination has been shown to be inferior
compared to protection conferred by COVID-19 vaccination after infection. Individuals who
have been infected but not vaccinated are around twice as likely to get re-infected than those
who have been fully vaccinated (2 doses). [5] Individuals who have been infected with COVID-
19 and then become re-infected are 5.5 times more likely to have a severe infection
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necessitating hospitalisation than those who have immunity through vaccination alone, 
noting this research was done before the emergence of the Omicron variant. [6] 
6. 
The Omicron variant has increasingly been associated with re-infection. It has been noted 
that approximately 65% of Omicron infections in England occurred in individuals who have 
previously had COVID-19 infection. [7]  
7. 
There are two sub-lineages of Omicron currently circulating in New Zealand, designated as 
BA.1 and BA.2. Non-peer reviewed research suggests that infection with one of these sub-
lineages has 85-95% effectiveness at preventing reinfection with the other, when evaluated at 
more than 35 days after infection. [8] However, it should be noted that the median follow-up 
time was only 2 weeks in this study, so at this stage it is challenging to ascertain how long 
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this immunity lasts or if it will protect from a new variant. Vaccination remains the best way to 
protect against new variants. 
ACT 
8. 
COVID-19 vaccination after infection is generally well-tolerated. Previous COVID-19 infection 
is associated with a slight increase in side effects after subsequent vaccination, particularly 
fatigue (29% vs 20%), myalgia (30% vs 15%), fever (8% vs 2%) and lymphadenopathy (4% vs 
1%),. [9] There are currently no reports of increased post-vaccine related myocarditis in those 
who have been vaccinated following infection. 
Status of overseas jurisdictions regarding COVID-19 vaccination after 
INFORMATION 
infection 
9. 
Currently, peak bodies representing Australia, Canada, United Kingdom, United States, and 
Singapore provide a range of recommendations regarding COVID-19 vaccination after 
infection.  
OFFICIAL 
10.  The Australian Technical Advisory Group for Immunisation (ATAGI) recommend that: 
[10] 
•
THE 
  Past SARS-CoV-2 infection is not a contraindication to vaccination. People who have had 
COVID-19 are advised to receive the same number of COVID-19 vaccine doses as people 
who have never been infected. 
•  People with SARS-CoV-2 infection can be vaccinated when they have recovered 
UNDER 
following their confirmed infection or can defer for up to 4 months after the onset of the 
infection (with or without symptoms). Commencement or continuation of further 
vaccination should not be deferred for more than 4 months. People who have prolonged 
symptoms of COVID-19 can still be vaccinated but the optimal timing should be 
determined on a case-by-case basis in consultation with their healthcare provider. 
•  Individuals sh
RELEASED  ould consider vaccination soon after infection and recovery if they: 
o  have a risk factor (e.g. an underlying medical condition) that puts them at high 
risk of severe disease from COVID-19 
o  have a higher risk of being exposed to COVID-19 (e.g. occupational risk factor) 
o  have not completed a COVID-19 vaccination primary course 
o  are unsure if they have had an infection with SARS-CoV-2 
•  Individuals can consider deferring vaccination for up to 4 months after the onset of 
infection if they are younger and have no risk factors for severe illness from COVID-19 
and they have recently completed their COVID-19 vaccination primary course. 
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•  Allowing a longer interval between recovery and vaccination may enhance the immune 
response to vaccination. Deferring vaccination after infection may also reduce the risk of 
misattribution of post-vaccination side effects to symptoms from post-COVID-19 
complications and vice versa. 
11.  The Canadian National Advisory Committee on Immunisation (NACI) recommends: [11] 
•  Individuals who experienced SARS-CoV-2 infection before starting or completing their 
primary COVID-19 vaccine series may receive their next dose 8 weeks after symptoms 
started or after testing positive (if no symptoms were experienced). 
•  Individuals who are recommended to receive a booster dose and who experienced 
SARS-CoV-2 infection after completing their primary series may receive a booster dose 3 
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months after symptoms started or after testing positive (if no symptoms were 
experienced) and provided it is at least 6 months after completing a primary series. 
ACT 
12.  In the United Kingdom, the Joint Committee on Vaccination and Immunisation (JCVI) 
recommend timing of vaccination for: [12] 
•  Adults - 4 weeks after onset of symptoms or from the first confirmed positive specimen. 
This interval may be reduced to ensure operational flexibility when rapid protection is 
required, for example high incidence or circulation of a new variant in a vulnerable 
population. 
•  Children 17 and under - 12 weeks from onset (or sample date) for those who are not in 
INFORMATION 
high-risk groups. This interval may be reduced to 8 weeks in healthy individuals when 
rapid protection is required. 
13.  In the US, the Centers for Disease Control and Prevention (CDC) recommends: [13] 
•  COVID-19 vaccination for everyone ages 5 years and older, regardless of a history of 
OFFICIAL 
symptomatic or asymptomatic SARS-CoV-2 infection. This includes people with 
prolonged post-COVID-19 symptoms and applies to primary series and booster 
THE 
doses. This recommendation also applies to people who experience SARS-CoV-2 
infection before or after receiving any COVID-19 dose. 
•  People with known current SARS-CoV-2 infection should defer any COVID-19 
vaccination, including booster vaccination, at least until recovery from the acute illness (if 
UNDER 
symptoms were present) and criteria to discontinue isolation have been met. Current 
evidence demonstrates a robust immune response to vaccination after infection, but 
information is lacking about whether and how the amount of time since infection affects 
the immune response to vaccination. 
14.  The Singaporean Ministry of Health recommends: [14] 
RELEASED 
•  Persons who had recovered from COVID-19 and were fully vaccinated before their 
infection are considered to have completed their primary series. Persons who have not 
completed their primary vaccination series before recovering from a COVID-19 infection, 
are recommended to receive a single dose of an mRNA vaccine. 
•  If the person is due for vaccination based on the schedules recommended in the national 
vaccination programme (e.g. to receive a booster dose about 5 months after two doses 
of mRNA vaccines), the person may receive the next vaccine dose 28 days after infection, 
although it is recommended to do so three months from the infection for better 
effectiveness. 
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Current recommendations in New Zealand 
15.
In February 2021, CV TAG provided advice regarding a booster dose after infection. It was
recommended that for those with PCR-confirmed COVID-19 infection after their primary
course, a COVID-19 vaccine booster dose should be offered 3 months after recovery from
acute illness.
16.
As at 17 February 2022, the New Zealand Immunisation Handbook advises that: [15]
• Vaccination should be offered regardless of an individual’s history of symptomatic or
asymptomatic SARS-CoV-2 infection.
• In a person who has had a previous SARS-CoV-2 infection, an individual is considered
fully vaccinated after two doses of mRNA-CV (or another COVID-19 vaccine). In these
individuals, vaccination is recommended 4 weeks after recovery, or 4 weeks from the first
confirmed positive PCR test if asymptomatic, and when cleared to leave isolation. This
ACT 1982
also applies to the second dose for individuals who have SARS-CoV-2 infection after
their first dose.
17.
The Immunisation Advisory Centre (IMAC) currently recommends that COVID-19 vaccination
can occur from 3 months after recovery from a COVID-19 infection, regardless of whether the
person has not had any vaccination doses, if they were not fully vaccinated (e.g., had one
dose only), or if they were fully vaccinated (e.g., had two doses). [16]
INFORMATION 
Recommendations 
18.
Given the differences in advice for timing of vaccination after infection, the COVID Vaccine
Immunisation Programme and IMAC have requested CV TAG recommendations for
clarification on this topic.
19.
CV TAG met on 8 March 2022 to discuss recommendations on COVID-19 vaccination after
infection in circumstances when the recommended course of vaccination has not been
completed.
20.
CV TAG noted that:
a) There is variation in the international advice on COVID-19 vaccination after infection.
b) Vaccination after infection has been shown to produce superior immune responses
compared to infection alone and is generally well-tolerated.
c) For children and adolescents, there has been less time for data to accumulate about
vaccination after infection than for adults, and data remain scarce in this age group.
21.
CV TAG recommends that:
a) COVID-19 vaccination (as per current schedule 
RELEASED UNDER THE OFFICIAL  and eligibility criteria) can occur any time
following infection, from the time of recovery from the acute illness (if symptoms were
present) and criteria to discontinue isolation have been met.
b) An interval of 3 months after infection is recommended as it allows for a better
immunological response to develop, particularly for 5-17-year-olds. The interval for 5-
17-year-olds should only be shorter in exceptional circumstances, where risk of COVID-
19 is clinically determined to outweigh the risk of an earlier vaccination. 
c) Clinical discretion can be applied when considering vaccination prior to 3 months after
infection. This may be appropriate for those individuals considered to be at high risk of
severe disease from COVID-19 re-infection.
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ACT 
INFORMATION 
OFFICIAL 
THE 
UNDER 
RELEASED 

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References 
1. 
Dan, J.M., et al., Immunological memory to SARS-CoV-2 assessed for up to 8 months after 
infection. Science, 2021. 371(6529). 
2. 
National institutes of Health. Lasting immunity found after recovery from COVID-19. 26 Jan 
2021; Available from: https://www.nih.gov/news-events/nih-research-matters/lasting-
immunity-found-after-recovery-covid-19. 
3. 
Liu, W., et al., Predictors of Nonseroconversion after SARS-CoV-2 Infection. Emerg Infect Dis, 
2021. 27(9): p. 2454-2458. 
4. 
Wellinghausen, N., et al., SARS-CoV-2-IgG response is different in COVID-19 outpatients and 
asymptomatic contact persons. J Clin Virol, 2020. 130: p. 104542. 
5. 
Cavanaugh, A.M., et al., Reduced Risk of Reinfection with SARS-CoV-2 After COVID-19 
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Vaccination — Kentucky, May–June 2021. MMWR. Morbidity and Mortality Weekly Report, 
2021. 70(32): p. 1081-1083. 
ACT 
6. 
Bozio, C.H., et al., Laboratory-Confirmed COVID-19 Among Adults Hospitalized with COVID-19-
Like Illness with Infection-Induced or mRNA Vaccine-Induced SARS-CoV-2 Immunity - Nine 
States, January-September 2021. MMWR Morb Mortal Wkly Rep, 2021. 70(44): p. 1539-1544. 
7. 
Elliott, P., et al. Post-peak dynamics of a national Omicron SARS-CoV-2 epidemic during January 
2022. medRxiv 2022; 2022.02.03.22270365]. Available from: 
http://medrxiv.org/content/early/2022/02/06/2022.02.03.22270365.abstract. 
8. 
Chemaitelly, H., et al. Protection of Omicron sub-lineage infection against reinfection with 
INFORMATION 
another Omicron sub-lineage. medRxiv 2022; 2022.02.24.22271440]. Available from: 
http://medrxiv.org/content/early/2022/02/25/2022.02.24.22271440.abstract. 
9. 
Raw, R.K., et al., Previous COVID-19 infection, but not Long-COVID, is associated with increased 
adverse events following BNT162b2/Pfizer vaccination. The Journal of infection, 2021. 83(3): p. 
381-412. 
OFFICIAL 
10. 
Australian Government Department of Health. Clinical recommendations for COVID-19 
vaccines. 2 March 2022; Available from: https://www.health.gov.au/initiatives-and-
programs/covid-19-vaccines/advice-fo
THE  r-providers/clinical-guidance/clinical-recommendations. 
11. 
Public Health Agency of Canada. Updated guidance on COVID-19 vaccination timing for 
individuals previously infected with SARS-CoV-2. 4 February 2022; Available from: 
https://www.canada.ca/content/dam/phac-aspc/documents/services/immunization/national-
advisory-committee-on-immu
UNDER nization-naci/naci-summary-rapid-response-updated-guidance-
covid-19-vaccination-timing-individuals-previously-infected-sars-cov-2.pdf. 
12. 
UK Government. COVID-19 Greenbook Chapter 14a. 28 February 2022; Available from: 
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment dat
a/file/1057798/Greenbook-chapter-14a-28Feb22.pdf. 
13. 
CDC. Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Approved or 
Authorized in the U
RELEASED  nited States. 22 February 2022; Available from: 
https://www.cdc.gov/vaccines/covid-19/clinical-considerations/covid-19-vaccines-us.html. 
14. 
Singapore Ministry of Health. FAQs - Booster Doses. 3 March 2022; Available from: 
https://www.moh.gov.sg/covid-19/vaccination/faqs---booster-doses. 
15. 
Ministry of Health New Zealand. Immunisation Handbook 2020, Chapter 5. Coronavirus disease 
(COVID-19). 17 February 2022; Available from: https://www.health.govt.nz/our-
work/immunisation-handbook-2020/5-coronavirus-disease-covid-19. 
16. 
The Immunisation Advisory Centre (IMAC). Vaccination after COVID-19 infection. 9 March 2022; 
Available from: https://covid.immune.org.nz/faq/vaccination-after-covid-19-infection. 
 
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