Syrian hamster convalescence from prototype SARS-CoV-2 confers measurable protection against the attenuated disease caused by the Omicron variant

The mutation profile of the SARS-CoV-2 Omicron (lineage BA.1) variant posed a concern for naturally acquired and vaccine-induced immunity. We investigated the ability of prior infection with an early SARS-CoV-2 ancestral isolate (Australia/VIC01/2020, VIC01) to protect against disease caused by BA.1. We established that BA.1 infection in naïve Syrian hamsters resulted in a less severe disease than a comparable dose of the ancestral virus, with fewer clinical signs including less weight loss. We present data to show that these clinical observations were almost absent in convalescent hamsters challenged with the same dose of BA.1 50 days after an initial infection with ancestral virus. These data provide evidence that convalescent immunity against ancestral SARS-CoV-2 is protective against BA.1 in the Syrian hamster model of infection. Comparison with published pre-clinical and clinical data supports consistency of the model and its predictive value for the outcome in humans. Further, the ability to detect protection against the less severe disease caused by BA.1 demonstrates continued value of the Syrian hamster model for evaluation of BA.1-specific countermeasures.

Neonatal lumbar puncture: are clinical landmarks accurate?

BACKGROUND

The intercristal line (ICL), defined by the superior aspect of the iliac crest, is used to clinically identify the entry point for lumbar puncture (LP) in neonates. Accepted practice is to insert the needle at the L3/4 or L4/5 intervertebral space.

AIM

To investigate the vertebral level crossed by the ICL as determined by manual palpation and the ability of manual palpation to reliably identify a specified intervertebral space.

METHOD

A total of 30 term neonates were recruited. Paediatricians identified and marked the ICL and the intervertebral space above, with babies in left lateral position. The anatomical positions of both points and the end of the conus medullaris were confirmed using ultrasonography.

RESULTS

The ICL was marked from L2/3 to L5/S1. In 25 babies (83%), the ICL was identified at the desired vertebral level between L3/4 and L4/5. The intervertebral space above this line was marked between L1/2 to L4/5. The potential site for LP was identified higher than intended in 11 cases (36%). The end of the conus medullaris ranged from L1 to L3 terminating at L2 or lower in 11 cases (36%).

CONCLUSIONS

There are wide variations in the positions of the ICL and potential LP site. Using the ICL to guide LP does not appear to be accurate, raising the possibility of potential spinal cord damage.