What if we’ve been measuring DNA contamination the wrong way?

A novel PCR method called LIDAR suggests conventional testing may miss much of the residual DNA in Covid-19 vaccines—helping explain why regulators and independent labs keep getting different results.

For several years, concerns over excessive DNA contamination in Covid-19 mRNA vaccines have been investigated almost entirely by independent scientists.

Researchers such as Kevin McKernan and David Speicher have continued to publish findings suggesting that levels of residual plasmid DNA in the vaccines exceed the regulatory limit of 10 nanograms per dose.

Regulators, meanwhile, have consistently maintained that their own testing shows residual DNA levels remain comfortably within acceptable limits.

Then, briefly last year, it appeared that these questions might finally receive official scrutiny.

The newly reconstituted Advisory Committee on Immunisation Practices (ACIP) signalled plans to examine previously overlooked manufacturing and quality issues, including DNA contamination.

Around the same time, FDA scientist Dr Tracy Høeg, then at the Centre for Biologics Evaluation and Research, publicly acknowledged that key scientific questions remained unanswered.

But that window of official inquiry closed quickly.

Following a federal court ruling, ACIP’s progress stalled, Hoeg is no longer at the FDA, and fundamental questions about residual DNA remain unresolved.

Once again, much of the work has fallen to independent scientists.

Now, genomics expert Kevin McKernan’s latest work brings us a step closer to a possible explanation for why measurements of residual DNA have differed so dramatically.

At first glance, his recent article is daunting. It runs for pages and is filled with technical language about PCR chemistry, molecular biology and laboratory engineering.

But for all its technical complexity, the central premise is fairly straightforward.