A second booster shot will be available from mid-June for people who are at high risk of getting very sick from
COVID-19.
The final decision on who is eligible will be made in the coming fortnight, but it will include the older population,
residents of aged care facilities and disability care facilities, and severely immunocompromised people.
The SMC asked experts to comment on the news. Feel free to use the comments below in your reporting or follow up with
the contact details provided.Professor Nikki Turner, Director Immunisation Advisory Centre, University of Auckland, comments:
"Overall vaccine effectiveness to severe disease is still high at six months after the first booster dose. However,
there are signs of waning immunity particularly for those who are older and more immunocompromised.
"From the USA, data vaccine effectiveness against hospitalisation (i.e., against more severe disease) following a course
of two doses plus a booster for adults over 50 years following three doses shows a drop off from 93 per cent (with
confidence intervals 91-94 per cent) at 14 – 59 days post the last vaccine to 84 per cent (CI 81-87 per cent) at 6 – 8
months post the last vaccine.
"However, this drop off is more marked for immunocompromised individuals where vaccine effectiveness to prevent
hospitalisation is around 50 per cent by 6 – 8 months post the last dose.
"A second dose adds a further level of protection for people 60 years and older. There is published data on the safety
and effectiveness of using a second booster dose from Israel. One study of over 1.1 million people 60 years and older
showed the fourth dose reduced the risk of confirmed infection by a factor of 2 (CI 2 – 2.1) and a reduction in severe
infection by 4.3 (CI 2.4 – 7.6) compared to those who had not received a fourth dose. Those who received a second
booster had a 78 per cent lower mortality rate from disease that those who only received one booster.
"A further Israeli study looked at over 1,000 healthcare workers over 18 years and showed there was a good safety
profile with no unexpected or severe adverse events."
Conflict of interest statement: Professor Turner is a member of the PITAG immunisation subcommiteee to Pharmac; Chair of
NVC – the measles national verification committee for the Ministry of Health; a member of the CVTAG – COVID-19 Technical
Advisory Group to the Ministry of Health; and a member of PHEAG – Strategic COVID-19 Public Health Advisory Group to the
government. The Immunisation Advisory Centre (IMAC) has a contract with the Ministry of Health to deliver clinical
advice, promotion, education and training to the healthcare sector for the national schedule vaccines and COVID-19
vaccines.