see also:

• COVID-19 coronavirus (2019-nCoV / SARS-CoV-2)
• COVID-19 risk and benefit of vaccination
• Aust Gov. patient handout of Pfizer vaccination
• Aust. govt patient handout of AZ vaccination risks
• SAFEVAC Adverse Reaction to Vaccines Reporting Process in Australia - note you should gain the patient's consent prior to reporting

• by far the most common reactions to Covid-19 vaccinations are:
  • vasovagal / anxiety which is likely to occur with any needle or vaccination
  • soreness, tenderness +/- erythema at vaccination site
    • this is common and is especially likely if vaccination is inadvertently given S/C instead of IM
  • general post-vax viral-like symptoms (eg. myalgias, headaches, sore throat, fevers/chills, enlarged lymph nodes, nausea, joint pains, etc) which are usually mild and last for a couple of days and can be managed by encouraging fluid intake, rest and paracetamol / non-steroidal anti-inflammatory drugs (NSAIDs)
    • some higher risk patients (eg. elderly, renal disease, transplant, cardiac failure) may develop dehydration with AKI, and resultant increased risk of postural hypotension and falls
    • rarely, it may precipitate herpes zoster (shingles)
• there are also a number of rare complications (less than 1 in 100,000) which may be serious and if vaccination rates are high such as over 100,000 per week then these may present to ED frequently enough to be included in work up decisions:
  • one possibility to explain some of these rare adverse effects is that inadvertent intravascular injection may be a factor in thrombocytopenia post AZ ¹⁾ and myocarditis post mRNA vaccines ²⁾ and such intravascular injection may cause immediate metallic taste within 10 seconds or so of injection
  • many of these would occur at similar or higher rates following a viral infection as many are related to the immune response to the vaccine which is similar to the response to a viral infection and as such a minority may develop auto-immune type illnesses such as:
  • myocarditis - predominantly after the second dose and predominantly in younger males (aged < 30 years) with peak incidence at 4-5 days after vaccination
    • https://mvec.mcri.edu.au/references/myocarditis-and-pericarditis-following-covid-19-mrna-vaccines/
  • pericarditis
    • mainly affects older patients after 1st or 2nd dose
  • subacute thyroiditis
  • new onset type 1 diabetes mellitus +/- diabetic ketoacidosis (DKA)
  • glomerulonephritis
  • rhabdomyolysis³⁾⁴⁾
  • severe haemolysis in patients with paroxysmal nocturnal hemoglobinuria usually within 1 day of an mRNA vaccine ⁵⁾
  • Guillain-Barre syndrome (GBS)
  • Idiopathic thrombocytopenic purpura (ITP)
  • aplastic anaemia / pancytopenia ⁶⁾
• the major concern though has been thrombosis with thrombocytopenia syndrome (TTS / VITT / VIPIT) after A-Z vaccination which occurs in some 1 in 50,000
  • rarely, 2 to 11 cases per million⁷⁾, patients have anaphylaxis which occurs very shortly after the vaccination
  • inadvertent injection into the shoulder joint from too high an injection site may cause Shoulder Injury Related to Vaccine Administration (SIRVA)
    • see https://mvec.mcri.edu.au/references/shoulder-injury-related-to-vaccine-administration/

• the far majority are benign vasovagal events and characterised by:
  • normal breathing with normal oxygen sats
  • strong, slow carotid pulse
  • bradycardia with transient hypotension and conscious state improved by lying down
  • sweaty, cold, pale skin
  • nausea +/- vomiting
  • often have PH of vasovagals
• rarely, approx. 1 in 100,000 may have anaphylaxis which will require immediate resuscitation with epinephrine, etc
  • differentiated from vasovagal by:
    • weak, fast carotid pulse
    • tachycardia with persistent hypotension and possibly reduced conscious state despite lying down
    • warm, pink skin +/- urticaria
    • possible upper airway swelling / angiooedema
    • possible cough/SOB/wheeze or stridor
    • possible respiratory distress such as rib retraction, hypoxia
    • onset can be delayed for an hour or so
  • note may also have vomiting, diarrhoea, abdominal cramps and sense of severe anxiety

• at risk persons who may develop dehydration if nausea and malaise reduces intakes +/- V&D after vaccination
  • elderly and frail
  • renal disease
  • renal transplant patients
  • cardiac failure
  • those taking NSAIDs, ACE inhibitors, diuretics
• management
  • may need to temporarily with-hold antihypertensives / diuretics
  • some may need IV fluids
  • if severe AKI or unusual features with AKI such as new proteinuria or haematuria arrange review by a nephrologist (may need to exclude glomerulonephritis)
  • need to monitor falls risk and postural hypotension

• the main concern here is pericarditis or myocarditis
• if patient is at very low risk for acute coronary syndrome or PE (eg age < 30 with no major risk factors), then the options for ED Mx are:
  • rapid assessment
  • ECG
  • if ECG unremarkable then either discharge home for F/U by GP or consider a single troponin
  • if ECG abnormal or troponin is elevated discuss with cardiology
  • Note that ATAGI also recommends a CXR but the resource implications for EDs perhaps outweigh their benefits
• if patient has risk factors for ACS or PE or dissection then Mx on their merits as per usual whilst adding in consideration of myocarditis
• NB. remember to consider vaccine-induced thyroiditis with thyrotoxicosis as a cause of palpitations, SOB - see below and check for a tender thyroid gland

• could it be subacute thyroiditis?
  • if the thyroid gland is tender then:
    • send bloods for FBE, U&E, CRP, TFTs
    • if CRP is high (usually > 50), T4 is very high, T3 is elevated and TSH < 0.1 then the diagnosis is very likely to be subacute thyroiditis
    • further Mx of presumed subacute thyroiditis:
      • ECG and clinical assessment for possible cardiac failure features
      • assess for ocular and myxoedema features that would suggest Graves disease - this is very unlikely if CRP is very high and the thyroid is tender.
      • send further bloods for:
        • ESR
        • antibodies to peroxidase, thyroglobulin and TSH receptor
      • consult with endocrine
      • if ongoing symptoms despite NSAIDs then:
        • 2-4 week course of high dose oral prednisolone:
          • 50mg/d 1st week, 37.5mg/day 2nd week, 25mg/d 3rd week, 12.5mg/d 4th week
          • some may start at the 37.5mg/d dosing if symptoms are not too severe
          • don't forget to warn patient of issues with high dose corticosteroids such as:
            • immune suppression - Covid vaccine probably will not be as protective
            • likely to cause instability with diabetics
            • potential cognitive issues
            • small risk (<1% at these doses) of spontaneous bone necrosis of hip/knee - reduce this by avoiding excess alcohol intake and aim for minimum course durations at doses above 40mg/day
            • advise patient to be tested EARLY if possible Covid-19 infection as at risk of severe illness due to immunocompromise and may be eligible for IV sotrovimab if presents before day 5
      • if symptoms of thyrotoxicosis:
        • start propranolol 20mg bd in young adults (perhaps 10mg bd initial dose in older adults)
      • repeat TFTs in 3-4 weeks and warn of risk of hypothyroidism developing and need for supplementary Rx with thyroxine
      • don't forget to report the adverse reaction!
• don't forget other causes such as:
  • Covid 19 infection
  • tonsillitis
  • peritonsillar abscess (quinsy)
  • EBV / glandular fever / infectious mononucleosis
  • gonococcal pharyngitis

• the main concern is thrombosis with thrombocytopenia syndrome (TTS / VITT / VIPIT) which unfortunately has a multitude of possible clinical presentations with onset AFTER day 4 such as:
  • headache
  • confusion
  • neurologic symptoms
  • chest pain
  • SOB
  • DVT
  • abdominal pain
• appears to occur in 1 in 50,000 in the 4-30 days after 1st dose vaccination with A-Z Covid-19 vaccine and is very rare after the 2nd dose.
• any patient with unexplained symptoms in this period should have a FBE to exclude thrombocytopenia
• if thrombocytopenia is present then do a D-Dimer pathology test and Ix as per thrombosis with thrombocytopenia syndrome (TTS / VITT / VIPIT)
• if thrombocytopenia is NOT present then it is very unlikely to be thrombosis with thrombocytopenia syndrome (TTS / VITT / VIPIT) although a repeat FBE in a couple of days may be considered

• bleeding/haematoma at injection site in those with bleeding disorders
  • vaccination is generally C/I in those with platelet count < 30 or INR > 3 ⁸⁾
    • patients with severe haemophilia should have dose AFTER usual prophylactic dose
    • patients on enoxaparin Rx or direct anticoagulants such as NOACs can have vax given PRIOR to dose
  • usual Rx of site bleeding is pressure.
• soreness, tenderness +/- erythema at vaccination site
  • this is common and is especially likely if vaccination is inadvertently given S/C instead of IM
  • local painful enlarged lymph nodes are also common and Mx is reassurance and analgesia
• restricted, painful shoulder joint movement
  • consider inadvertent injection into the shoulder joint from too high an injection site which may cause Shoulder Injury Related to Vaccine Administration (SIRVA)
    • see https://mvec.mcri.edu.au/references/shoulder-injury-related-to-vaccine-administration/