The effect of needle length and skin to deltoid muscle distance in adults receiving an mRNA COVID-19 vaccine

Efficacy, Immunogenicity, and Safety of COVID-19 Vaccines in Patients with Autoimmune Diseases: A Systematic Review and Meta-Analysis

Patients with autoimmune diseases are among the susceptible groups to COVID-19 infection because of the complexity of their conditions and the side effects of the immunosuppressive drugs used to treat them. They might show impaired immunogenicity to COVID-19 vaccines and have a higher risk of developing COVID-19. Using a systematic review and meta-analysis, this research sought to summarize the evidence on COVID-19 vaccine efficacy, immunogenicity, and safety in patients with autoimmune diseases following predefined eligibility criteria. Research articles were obtained from an initial search up to 26 September 2022 from PubMed, Embase, EBSCOhost, ProQuest, MedRxiv, bioRxiv, SSRN, EuroPMC, and the Cochrane Center of Randomized Controlled Trials (CCRCT). Of 76 eligible studies obtained, 29, 54, and 38 studies were included in systematic reviews of efficacy, immunogenicity, and safety, respectively, and 6, 18, and 4 studies were included in meta-analyses for efficacy, immunogenicity, and safety, respectively. From the meta-analyses, patients with autoimmune diseases showed more frequent breakthrough COVID-19 infections and lower total antibody (TAb) titers, IgG seroconversion, and neutralizing antibodies after inactivated COVID-19 vaccination compared with healthy controls. They also had more local and systemic adverse events after the first dose of inactivated vaccination compared with healthy controls. After COVID-19 mRNA vaccination, patients with autoimmune diseases had lower TAb titers and IgG seroconversion compared with healthy controls.

When should a longer needle be used for intramuscular injection in obese patients? A combined analysis of New Zealand data

AIM

To estimate thresholds for Body Mass Index (BMI) and arm circumference above which a longer needle is needed to ensure intramuscular (IM) delivery of a vaccine in the deltoid muscle at the site recommended by New Zealand (NZ) immunization guidelines.

METHODS

A combined analysis of two studies, including 442 adults, with measurements of arm circumference, BMI and skin to deltoid muscle distance (SDMD) at the NZ immunization guideline-recommended IM injection site. Receiver Operator Characteristic curves identified arm circumference and BMI cut-points that gave 100% sensitivity for SDMD thresholds. These thresholds were: SDMD of 20 mm, accounting for a minimal penetration of 5 mm into muscle with the standard needle; and 25 mm, which is the length of a standard needle for IM injection, representing the depth this can reach.

RESULTS

Cut-point values for arm circumference, at which a longer needle would be required, were higher for males than females: 35 cm versus 30 cm for the 20 mm cut-point, and 40 cm versus 36.7 cm for the 25 mm cut-point respectively. The BMI cut-points were also higher for male than females: 24.6 kg/m² versus 23.7 kg/m² for the 20 mm cut-point, and 38.2 kg/m² vs 31.6 kg/m² for the 25 mm cut-point respectively.

CONCLUSION

Arm circumference and BMI cut-points provide practical measures from which to choose a needle length that increases the chance of successful IM vaccination. Based on our data, an arm circumference of 35 cm for men and 30 cm for women should prompt selection of a longer needle to ensure intramuscular injection at the deltoid site. Thresholds for the different skin to deltoid sites proposed internationally should be determined to enable successful IM vaccination in clinical practice beyond NZ.

Immunogenicity of BNT162b2 COVID-19 vaccine in New Zealand adults

Background

There is very little known about SARS-CoV-2 vaccine immune responses in New Zealand populations at greatest risk for serious COVID-19 disease.

Methods

This prospective cohort study assessed immunogenicity in BNT162b2 mRNA vaccine recipients in New Zealand without previous COVID-19, with enrichment for Māori, Pacific peoples, older adults ≥ 65 years of age, and those with co-morbidities. Serum samples were analysed at baseline and 28 days after second dose for presence of quantitative anti-S IgG by chemiluminescent microparticle immunoassay and for neutralizing capacity against Wuhan, Beta, Delta, and Omicron BA.1 strains using a surrogate viral neutralisation assay.

Results

285 adults with median age of 52 years were included. 55% were female, 30% were Māori, 28% were Pacific peoples, and 26% were ≥ 65 years of age. Obesity, cardiac and pulmonary disease and diabetes were more common than in the general population. All participants received 2 doses of BNT162b2 vaccine. At 28 days after second vaccination, 99.6% seroconverted to the vaccine, and anti-S IgG and neutralising antibody levels were high across gender and ethnic groups. IgG and neutralising responses declined with age. Lower responses were associated with age ≥ 75 and diabetes, but not BMI. The ability to neutralise the Omicron BA.1 variant in vitro was severely diminished but maintained against other variants of concern.

Conclusions

Vaccine antibody responses to BNT162b2 were generally robust and consistent with international data in this COVID-19 naïve cohort with representation of key populations at risk for COVID-19 morbidity. Subsequent data on response to boosters, durability of responses and cellular immune responses should be assessed with attention to elderly adults and diabetics.