Et forskerpar i vacciner ved Syddansk Universitet, Christine Stabell Benn og Peter Aaby, er af kritikere blevet beskyldt for systematisk at oversælge deres forskningsresultater. 

Det er et kendt fænomen, at forskere af og til oversælger eller »spinner« deres resultater, så de ser ud til at være mere overbevisende, end de faktisk er. Ofte ser man, at en videnskabelig artikels konklusion giver udtryk for, at en hypotese er stærk, selvom resultaterne ikke var statistisk signifikante og dermed ikke understøttede hypotesen.

Kritikerne mener, at Stabell Benn og Aaby – som beskrevet i Weekendavisen – bruger oversolgte ikkesignifikante studier til at promovere deres hypotese om, at vacciner har uspecifikke effekter på immunsystemet.   

Weekendavisen har her samlet nogle af de eksempler, som kritikerne fremhæver:

Videnskabelige artikler

Oral Polio Vaccine to Mitigate the Risk of Illness and Mortality During the Coronavirus Disease 2019 Pandemic: A Cluster-Randomized Trial in Guinea-Bissau

Forsøget skulle undersøge, om den levende, orale poliovaccine beskyttede mod covid-19. Resultatet viste ingen forskel blandt de vaccinerede og uvaccinerede, men i konklusionen blev et statistisk signifikant fund i en undergruppe (mænd) i stedet fremhævet:

»In line with previous studies, OPV had beneficial nonspecific effects in males.«

Early BCG-Denmark and Neonatal Mortality Among Infants Weighing <2500 g: A Randomized Controlled Trial

Forsøget skulle undersøge, om tuberkulosevaccinen BCG kunne sænke dødeligheden hos for tidligt fødte børn. Det fandt forsøget ikke evidens for, men en metaanalyse af tre af forskergruppens egne forsøg blev tilføjet i artiklen, og derfor blev konklusionen til: »Early administration of BCG-Denmark in LW (lav vægt, red.) infants is associated with major reductions in mortality rate.«

Small Randomized Trial Among Low-birth-weight Children Receiving Bacillus Calmette-Guérin Vaccination at First Health Center Contact

En mindre gruppe børn, 105 i alt, blev udtaget fra et større forsøg. Formålet var at undersøge BCG-vaccinens effekt på dødeligheden hos for tidligt fødte børn. Resultatet var ikke signifikant, men konklusionen lyder: »Administration of BCG vaccine at first contact may contribute to lower mortality.«

The Effect of Oral Polio Vaccine at Birth on Infant Mortality: A Randomized Trial

Studiet skulle undersøge den levende, orale poliovaccines effekt på spædbørnsdødeligheden. Resultatet var ikke signifikant, men konklusionen lyder:

»This is the only randomized trial of the effect of OPV0 on mortality. OPV0 may be associated with nonspecific protection against infectious disease mortality, particularly when given early in life.«

The effect of early measles vaccination at 4.5 months of age on growth at 9 and 24 months of age in a randomized trial in Guinea-Bissau

Studiet undersøgte effekten af mæslingevaccinen på børns vækst. Der blev ikke fundet nogen signifikant effekt. Konklusionen lyder:

»Early MV was associated with a larger MUAC (overarmsomkreds, red.) particularly in girls. These results indicate that a two-dose measles vaccination schedule might not only reduce child mortality but also improve growth.«

Non-specific effects of standard measles vaccine at 4.5 and 9 months of age on childhood mortality: randomised controlled trial

Samme forsøg som ovenstående, men hvor formålet var at teste, om mæslingevaccinen havde effekt på børnedødeligheden. Resultatet var ikke signifikant. Konklusionen lyder:

»Although the overall effect did not reach statistical significance, the results may indicate that a two dose schedule with Edmonston-Zagreb measles vaccine given at 4.5 and 9 months of age has beneficial nonspecific effects on children’s survival, particularly for girls and for children who have not received neonatal vitamin A.«

Randomized Trial of 2 Versus 1 Dose of Measles Vaccine: Effect on Hospital Admission of Children After 9 Months of Age

Samme forsøg som de to ovenstående. Studiet afrapporterer på det sekundære udfald om effekt af mæslingevaccinen på hospitalsindlæggelser. Resultatet var ikke signifikant. Konklusionen omhandler dog i stedet en undergruppe, hvor effekten var signifikant.:

»The benefit of 2 doses of MV was limited to children who had not received NVAS. NVAS is not generally recommended; hence, an early 2-dose measles vaccination policy might reduce hospital admissions more than the current policy of providing the first MV at 9 months of age.«

Kommentarer, reviews og perspektivartikler:

How to evaluate potential non-specific effects of vaccines: the quest for randomized trials or time for triangulation?

Artiklen diskuterer, om kliniske studier er den eneste måde at undersøge uspecifikke vaccineeffekter på. I introduktionen står der:

»There is increasing evidence that vaccines have important non-specific effects (NSEs), i.e. that they affect susceptibility to unrelated infections, with important effects on overall mortality and morbidity[1].«

Henvisning 1 er til en anden gennemgang skrevet af Bandim-forskere: A small jab – a big effect: nonspecific immunomodulation by vaccines

Her står: »A series of observational studies found nonspecific effects for all the routine childhood vaccines, and randomized trials were initiated. These trials confirmed that the standard measles vaccine [4,5] and BCG vaccine [6,7] actually have beneficial nonspecific effects.«

De fire henvisninger, 4, 5, 6, 7, er til disse videnskabelige artikler fra Bandim, som alle rapporterer om ikkesignifikante fund, eller som ikke omhandler et specifikt forsøg:

  1. Non-specific effects of standard measles vaccine at 4.5 and 9 months of age on childhood mortality: randomised controlled trial | The BMJ

  2. The optimal age of measles immunisation in low-income countries: a secondary analysis of the assumptions underlying the current policy | BMJ Open

  3. Randomized trial of BCG vaccination at birth to low-birth-weight children: beneficial nonspecific effects in the neonatal period? – PubMed

  4. Small randomized trial among low-birth-weight children receiving bacillus Calmette-Guérin vaccination at first health center contact

A Two-Center Randomized Trial of an Additional Early Dose of Measles Vaccine: Effects on Mortality and Measles Antibody Levels

Artiklen omhandler effekten af at give en ekstra tidlig dosis mæslingevaccine. Resultatet var ikke signifikant. I litteraturgennemgangen skriver forskerne:

»Such beneficial NSEs have also been shown for other live vaccines such as BCG [12-14] and oral polio vaccine (OPV) [15].«

Referencerne 12, 13, 14 og 15 er alle til egne ikkesignifikante fund. Reference 13 indeholder dog også den metaanalyse med et signifikant fund, som er omtalt herover.

  1. Randomized trial of BCG vaccination at birth to low-birth-weight children: beneficial nonspecific effects in the neonatal period?

  2. Early BCG-Denmark and Neonatal Mortality Among Infants Weighing <2500 g: A Randomized Controlled Trial

  3. Small randomized trial among low-birth-weight children receiving bacillus Calmette-Guérin vaccination at first health center contact

  4. The Effect of Oral Polio Vaccine at Birth on Infant Mortality: A Randomized Trial

Beneficial non-specific effects of live vaccines against COVID-19 and other unrelated infections – The Lancet Infectious Diseases

Artiklen er en kommentar og handler om, at visse vacciner muligvis kunne beskytte mod covid-19. I introduktionen skriver de:

»Live attenuated vaccines have been linked to beneficial non-specific effects, such as reductions in mortality that are not explained by preventing the vaccine-targeted disease.[1-6] Randomised clinical trials (RCTs) have repurposed measles vaccines, the BCG vaccine against tuberculosis, and oral polio vaccine (OPV) to reduce child mortality by providing protection against vaccine-unrelated infections.[1-6].«

Referencerne 1, 2, 3, 4, 5, 6 er til disse seks nedenstående artikler. Den første er et af deres egne tidligere reviews. De fire næste er egne studier med ikkesignifikante hovedresultater. Den sjette er et studie fra Uganda, som fandt en signifikant effekt af tuberkulosevaccinen på risikoen for, at nyfødte blev smittet med infektionssygdomme.

  1. Vaccinology: Time to Change the Paradigm?

  2. Non-specific effects of standard measles vaccine at 4.5 and 9 months of age on childhood mortality: randomised controlled trial

  3. The Effect of Oral Polio Vaccine at Birth on Infant Mortality: A Randomized Trial

  4. Randomized trial of BCG vaccination at birth to low-birth-weight children: beneficial nonspecific effects in the neonatal period?

  5. Early BCG-Denmark and Neonatal Mortality Among Infants Weighing <2500 g: A Randomized Controlled Trial

  6. BCG-induced non-specific effects on heterologous infectious disease in Ugandan neonates: an investigator-blind randomised controlled trial

Christine Stabell Benn og Syddansk Universitet er blevet forelagt listen med eksemplerne, men er ikke vendt tilbage på henvendelsen.