An Australian vaccine sceptic claims “you can’t actually vaccinate” against respiratory diseases because the vaccines are “bypassing the oral-nasal” region.
But experts say the claim is false. Injected vaccines have proven effective against respiratory diseases including influenza and COVID-19. Vaccines prompt an immune response that sends antibodies to the infected area of the respiratory tract.
Ms Hart based her comments on previous claims by Australian former immunologist Edward J. Steele that intramuscular vaccines injected into the arm were incapable of activating immunity in the upper respiratory tract where coronavirus develops (video mark 1min 20sec).
“The statement ‘you can’t vaccinate against respiratory diseases’ is inaccurate as it fails to appreciate the spectrum of respiratory diseases,” Dr Bartlett said in an email.
“Vaccines injected into the arm stimulate systemic immunity which is very good at preventing severe respiratory (lung) disease.
“Influenza and COVID vaccines injected into the arm have saved millions of lives by protecting against an otherwise fatal respiratory disease.”
Associate Professor Helen Petousis-Harris, a vaccine expert at the University of Auckland, told AAP FactCheck that injected vaccines work against infections by generating antibodies that migrate to the infected tissue.
COVID-19 mRNA vaccines, for example, induce antibodies found in the respiratory system and saliva, Dr Petousis-Harris said in an email.
“The reason that vaccines given as injection are effective against infections that enter through the respiratory route is firstly, the type of antibody found in mucosal membranes such as those found in the respiratory system (IgA) can be generated via injection,” she said.
“(Secondly) when the body detects an infection in the respiratory system it alerts the immune memory generated by the vaccine. The immune response that ensues includes cells and antibody that migrate to the infected tissue.
“It is a very peculiar claim given that injectable vaccines against respiratory infections have been used very successfully for around 100 years.”
“The only reason we need boosters each year is the emergence of variants or mismatches between circulating strains (in the case of flu). Otherwise, the immunity we get through the muscular injection is good and protective,” she said.
The effectiveness of COVID-19 vaccines has waned significantly since their global rollout in 2021. However, this July 2022 Australian study found that modifying booster shots to tackle new variants could increase vaccine effectiveness by around 50 per cent.
Dr Labzin said nasal COVID-19 vaccines may prove to be a better “rapid response” for infections in the respiratory tract than injected vaccines because they go directly to the site of the infection to stimulate mucosal antibodies that aren’t stimulated well by intramuscular vaccines.
However, it is not yet clear if nasal spray vaccines will work against COVID-19, she said.
“Being vaccinated (through injection) is still the best and safest protection against severe disease. One day in the future we’ll hopefully have broad-spectrum vaccines that can be administered intra-nasally so we can also block transmission,” Dr Labzin said.
Dr Petousis-Harris agreed that the effectiveness of nasal COVID-19 vaccines has not yet been proven.
“Vaccines given intranasally might have an advantage for some types of respiratory infections. Intranasal influenza vaccine has been used in children for many years,” she said.
“It is yet to be demonstrated if an intranasal COVID-19 vaccine will have significant benefits over injectable vaccines.”
The claim that injected vaccines do not work against respiratory illnesses is incorrect. Multiple experts confirmed to AAP FactCheck that injected vaccines have proven effective against a range of respiratory illnesses over many years.
False – The claim is inaccurate.